// Numbas version: finer_feedback_settings {"allQuestions": true, "name": "Numerical reasoning - ratio and percentage", "question_groups": [{"pickingStrategy": "all-ordered", "name": "", "questions": [{"name": "Numerical Reasoning - percentage increase in price", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {}, "tags": ["maths-aid", "money", "numerical reasoning", "percentage", "profit"], "advice": "
Think of the cost to produce as being 100%. The price is {percent}% greater, so is {percent+100}% of the cost, i.e. $\\frac{\\var{percent+100}}{100}$ of the cost.
\nHence the cost is $\\frac{100}{\\var{percent+100}} = \\simplify{100/{percent+100}}$ of the price = $\\simplify{100/{percent+100}} \\times £\\var{dpformat(sell,2)} = £\\var{produce}$.
\nThe profit = selling price - cost = £{dpformat(sell,2)} - £{produce} = £{dpformat(sell-produce,2)}.
", "rulesets": {}, "parts": [{"prompt": "How much did it cost to produce the {thing[1]} and what was the profit?
\nCost to produce: £ [[0]]
\nProfit: £ [[1]]
", "gaps": [{"minvalue": "produce", "type": "numberentry", "maxvalue": "produce", "marks": 1.0, "showPrecisionHint": false}, {"minvalue": "sell-produce", "type": "numberentry", "maxvalue": "sell-produce", "marks": 1.0, "showPrecisionHint": false}], "type": "gapfill", "marks": 0.0}], "statement": "The selling price of {thing[0]} is £{dpformat(sell,2)}.
\nThis price was {percent}% greater than the cost to produce the {thing[1]}.
", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"sell": {"definition": "produce*(1+percent/100)", "name": "sell"}, "thing": {"definition": "random(['a box of chocolates','box'],['an action figure','toy'],['a scarf','scarf'])", "name": "thing"}, "produce": {"definition": "random(3..12 except 10)", "name": "produce"}, "percent": {"definition": "random(10..60#5)", "name": "percent"}}, "metadata": {"notes": "", "description": "Given the selling price of an item both as a cash amount and as a percentage of the cost of production, find the cost of production and the profit.
\nBased on question 1 from section 3 of the Maths-Aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Numerical Reasoning - percentage enlargement", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {}, "ungrouped_variables": ["dir1", "dir2", "final", "prop1", "prop2", "prop2rel", "verbed1", "verbed2"], "tags": ["maths-aid", "numerical reasoning", "percentage", "Proportion", "proportion", "ratio"], "advice": "The picture has been {verbed1} to {prop1}% or $\\simplify{{prop1}/100} \\left(=\\frac{\\var{prop1}}{100}\\right)$ of its original size.
\nSo to find the size of the first copy we multiply the original size by $\\simplify{{prop1}/100}$.
\nIf we then {verbed2} the new size by {prop2}%, the final copy would be {prop2rel}% of the size of the first copy, i.e. $\\simplify{{prop2rel}/100}$ of the size of the first copy.
\nTo get the size of the final copy as a proportion of the size of the original copy, we multiply $\\simplify{{prop1}/100}$ by $\\simplify{{prop2rel}/100}$ to get
\n\\[\\simplify{{prop1}/100} \\times \\simplify{{prop2rel}/100} = \\simplify{{prop1*prop2rel}/10000}\\]
\nNow to express this as a percentage we multiply by 100 and we obtain:
\n\\[\\simplify{{prop1*prop2rel}/10000} \\times 100 = \\var{final}\\%.\\]
\nSo the final copy is {final}% of the size of the original picture.
", "rulesets": {}, "parts": [{"prompt": "What percentage of the size of the original picture was the final copy?
\n[[0]] %
", "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "gaps": [{"allowFractions": false, "variableReplacements": [], "maxValue": "final", "minValue": "final", "variableReplacementStrategy": "originalfirst", "correctAnswerFraction": false, "showCorrectAnswer": true, "scripts": {}, "marks": 1, "type": "numberentry", "showPrecisionHint": false}], "showCorrectAnswer": true, "scripts": {}, "marks": 0, "type": "gapfill"}], "statement": "A picture on a page was {verbed1} on a copier to {prop1}% of its original size, and this copy was then {verbed2} by {prop2}%.
", "variable_groups": [], "variablesTest": {"maxRuns": 100, "condition": ""}, "preamble": {"css": "", "js": ""}, "variables": {"dir2": {"definition": "random(1,-1)", "templateType": "anything", "group": "Ungrouped variables", "name": "dir2", "description": ""}, "dir1": {"definition": "random(1,-1)", "templateType": "anything", "group": "Ungrouped variables", "name": "dir1", "description": ""}, "prop2rel": {"definition": "100+dir2*prop2", "templateType": "anything", "group": "Ungrouped variables", "name": "prop2rel", "description": ""}, "prop1": {"definition": "100+dir1*random(10..40#10)", "templateType": "anything", "group": "Ungrouped variables", "name": "prop1", "description": ""}, "prop2": {"definition": "random(10..40#10)", "templateType": "randrange", "group": "Ungrouped variables", "name": "prop2", "description": ""}, "verbed2": {"definition": "if(dir2=1,'increased','reduced')", "templateType": "anything", "group": "Ungrouped variables", "name": "verbed2", "description": ""}, "verbed1": {"definition": "if(dir1=1,'increased','reduced')", "templateType": "anything", "group": "Ungrouped variables", "name": "verbed1", "description": ""}, "final": {"definition": "(prop1/100)*(100+dir2*prop2)", "templateType": "anything", "group": "Ungrouped variables", "name": "final", "description": ""}}, "metadata": {"notes": "", "description": "Scale a page to some percentage of its original size, then increase/decrease by another percentage. Find the size of the final copy as a percentage of the original.
\nBased on question 2 from section 3 of the Maths-Aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "type": "question", "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Numerical reasoning - percentages of subsets", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {}, "tags": ["numerical reasoning", "percentages", "ratio"], "advice": "Calculate separately the percentage of employees who are female and working on the project, and the percentage who are male and working on the project, and add them together.
\n{females}% of the department is female and {femaleproject}% of females are working on the project, hence the proportion of workers who are female and working on the project is {femaleproject}% of {females}% of the workers.
\nIn terms of fractions this is \\[ \\frac{\\var{femaleproject}}{100} \\times \\frac{\\var{females}}{100} = \\frac{\\var{femaleproject*females}}{10000} = \\frac{\\var{depfemaleproject}}{100}\\] of the workers, ie {depfemaleproject}%.
\nSo {depfemaleproject}% of the departmental staff are working on the project and female.
\n\n
{males}% of the department is male and {maleproject}% of males are working on the project, hence the proportion of workers who are male and working on the project is {maleproject}% of {males}% of the workers.
\nIn terms of fractions this is \\[ \\frac{\\var{maleproject}}{100} \\times \\frac{\\var{males}}{100} = \\frac{\\var{maleproject*males}}{10000} = \\frac{\\var{depmaleproject}}{100}\\] of the workers, ie {depmaleproject}%.
\nSo {depmaleproject}% of the departmental staff are working on the project and male.
\nSo the total percentage of departmental staff working on the project is $\\var{depfemaleproject}\\% + \\var{depmaleproject}\\% = \\var{project}\\%$.
\n", "rulesets": {}, "parts": [{"prompt": "
What percentage of the department is working on the project?
\n[[0]] %
", "gaps": [{"minvalue": "{project}", "type": "numberentry", "maxvalue": "{project}", "marks": 1.0, "showPrecisionHint": false}], "type": "gapfill", "marks": 0.0}], "statement": "In a certain department, {femaleproject}% of the females and {maleproject}% of the males are working on a project. {if(describefemales,females,males)}% of the department is {if(describefemales,'female','male')}.
", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"females": {"definition": "//percentage of all employees who are female\n random(20..80#5)", "name": "females"}, "describefemales": {"definition": "//Give the percentage of females in the statement, or give the males?\n random(true,false)", "name": "describefemales"}, "femaleproject": {"definition": "//percentage of females working on the project\n random(10..90#10)", "name": "femaleproject"}, "males": {"definition": "//percentage of all employees who are male\n 100-females", "name": "males"}, "depmaleproject": {"definition": "//proportion of employees who are male and working on the project\n maleproject*males/100", "name": "depmaleproject"}, "project": {"definition": "//total percentage of the department working on the project\n (females*femaleproject+males*maleproject)/100", "name": "project"}, "depfemaleproject": {"definition": "//proportion of employees who are female and working on the project\n femaleproject*females/100", "name": "depfemaleproject"}, "maleproject": {"definition": "//percentage of males working on the project\n random(10..90#10)", "name": "maleproject"}}, "metadata": {"notes": "", "description": "Given percentages of males and females working on a project, and the percentage of the total staff who are male (or female), find the percentage of all staff working on the project.
\nBased on question 3 from section 3 of the maths-aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Numerical reasoning - prices in ratios", "extensions": ["stats"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {"describefraction": {"definition": "//put fraction into words\n \n numbers = ['zero','one','two','three','four','five','six','seven','eight','nine','ten'];\n denominators = ['','','half','third','quarter','fifth','sixth','seventh','eighth','ninth','tenth'];\n \n var gcd = Numbas.math.gcf(n,d);\n n /= gcd;\n d /= gcd;\n \n if(n%d==0) {\n var t = n/d;\n switch(t) {\n case 1:\n return 'the same as';\n case 2:\n return 'twice as much as';\n default:\n return numbers[t]+' times as much as';\n }\n }\n else if(n>d) {\n var t = (n-(n%d))/d;\n var m = n%d;\n if(m==1)\n return numbers[t]+'-and-a-'+denominators[d]+' times as much as';\n else\n return numbers[t]+'-and-'+numbers[m]+'-'+denominators[d]+(m>1?'s':'')+' times as much as';\n }\n else if(d==2) {\n return 'half as much as';\n }\n else {\n return numbers[n]+'-'+denominators[d]+(n>1?'s':'')+' as much as';\n }", "type": "string", "language": "javascript", "parameters": [["n", "number"], ["d", "number"]]}, "pluralise": {"definition": "return Numbas.util.pluralise(n,singular,plural);", "type": "string", "language": "javascript", "parameters": [["n", "number"], ["singular", "string"], ["plural", "string"]]}, "capitalise": {"definition": "return Numbas.util.capitalise(s);", "type": "string", "language": "javascript", "parameters": [["s", "string"]]}}, "tags": ["constraints", "numerical reasoning", "ratio", "simultaneous equations"], "advice": "Here are two solutions. The first uses the idea of shares and the second uses algebra.
\nWe are given that the cost of \\[ \\var{ratio[dirs[1]]/gcd(ratio[dirs[0]],ratio[dirs[1]])} \\times \\var{ops[dirs[0]]} = \\var{ratio[dirs[0]]/gcd(ratio[dirs[0]],ratio[dirs[1]])} \\times \\var{ops[dirs[1]]} \\] and \\[ \\var{ratio[dirs[2]]/gcd(ratio[dirs[1]],ratio[dirs[2]])} \\times \\var{ops[dirs[1]]} = \\var{ratio[dirs[1]]/gcd(ratio[dirs[1]],ratio[dirs[2]])} \\times \\var{ops[dirs[2]]}. \\]
\nWe can represent the ratios of the costs for {ops[dirs[0]]}, {ops[dirs[1]]} and {ops[dirs[2]]} by giving cost shares to each of the repairs in the ratios {ratio[dirs[0]]}:{ratio[dirs[1]]}:{ratio[dirs[2]]}.
\nThat is, give {ops[dirs[0]]} {ratio[dirs[0]]} {pluralise(ratio[dirs[0]],'share','shares')}, {ops[dirs[1]]} {ratio[dirs[1]]} {pluralise(ratio[dirs[1]],'share','shares')} and {ops[dirs[2]]} {ratio[dirs[2]]} {pluralise(ratio[dirs[2]],'share','shares')}. Then the relative costs are preserved.
\nHence there are $\\var{ratio[dirs[0]]}+\\var{ratio[dirs[1]]}+\\var{ratio[dirs[2]]} = \\var{ratiototal}$ shares to add up to £{total}.
\nSo each share is worth $\\var{total} \\div \\var{ratiototal} = £\\var{factor}$ and {ops[wanted]} gets {ratio[wanted]} {pluralise(ratio[wanted],'share','shares')} i.e. costs £{prices[wanted]}.
\nLet $\\var{letters[0]}$ = {ops[0]}, $\\var{letters[1]}$ = {ops[1]}, $\\var{letters[2]}$ = {ops[2]}.
\nWe are given that $\\var{letters[dirs[0]]} = \\simplify{{ratio[dirs[0]]}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]}$, and $\\var{letters[dirs[1]]} = \\simplify{{ratio[dirs[1]]}/{ratio[dirs[2]]}} \\var{letters[dirs[2]]}$.
\nRearrange the second equation to give $\\var{letters[dirs[2]]}$ in terms of $\\var{letters[dirs[1]]}$:
\n\\[ \\var{letters[dirs[2]]} = \\simplify{{ratio[dirs[2]]}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]} \\]
\nSo \\[ \\begin{eqnarray} \\textrm{total cost of repair work} &=& \\var{letters[dirs[0]]} + \\var{letters[dirs[1]]} + \\var{letters[dirs[2]]} \\\\ &=& \\simplify{{ratio[dirs[0]]}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]} + \\var{letters[dirs[1]]} + \\simplify{{ratio[dirs[2]]}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]} \\\\ &=& \\left( \\simplify{{ratio[dirs[0]]}/{ratio[dirs[1]]}} + 1 + \\simplify{{ratio[dirs[2]]}/{ratio[dirs[1]]}} \\right) \\var{letters[dirs[1]]} \\\\ &=& \\simplify{{ratiototal}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]}. \\end{eqnarray} \\]
\nHence $\\simplify{{ratiototal}/{ratio[dirs[1]]}} \\var{letters[dirs[1]]} = £\\var{total}$ gives us $\\var{letters[dirs[1]]} = \\simplify{{ratio[dirs[1]]}/{ratiototal}} \\times £\\var{total} = £\\var{prices[dirs[1]]}$.
\nSo the cost of {ops[wanted]} was £{prices[wanted]}.
", "rulesets": {}, "parts": [{"prompt": "What did {ops[wanted]} cost?
\n£ [[0]]
", "gaps": [{"minvalue": "{prices[wanted]}", "type": "numberentry", "maxvalue": "{prices[wanted]}", "marks": 1.0, "showPrecisionHint": false}], "type": "gapfill", "marks": 0.0}], "statement": "The total cost for three items of work on a {car} was £{total}.
\nThese items were: {ops[0]}, {ops[1]} and {ops[2]}.
\n{capitalise(ops[dir1[0]])} costs {describefraction(ratio[dir1[0]],ratio[dir1[1]])} {ops[dir1[1]]}.
\n{capitalise(ops[dir2[0]])} costs {describefraction(ratio[dir2[0]],ratio[dir2[1]])} {ops[dir2[1]]}.
", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"dirs": {"definition": "shuffle([0,1,2])", "name": "dirs"}, "dir2": {"definition": "[dirs[1],dirs[2]]", "name": "dir2"}, "dir1": {"definition": "[dirs[0],dirs[1]]", "name": "dir1"}, "wanted": {"definition": "dirs[1]", "name": "wanted"}, "letters": {"definition": "map(allops[j][1],j,0..2)", "name": "letters"}, "r1": {"definition": "random(possibleratios)", "name": "r1"}, "r2": {"definition": "random(possibleratios except r1)", "name": "r2"}, "ops": {"definition": "map(allops[j][0],j,0..2)", "name": "ops"}, "allops": {"definition": "shuffle([['overhauling the carburettor','C'],['replacing the brake pads','B'],['refilling the air-con','A'],['replacing the gearbox','G'],['balancing the wheels','W']])[0..3]", "name": "allops"}, "r3": {"definition": "random(possibleratios except [r1,r2])", "name": "r3"}, "f2": {"definition": "lcm(ratio[dirs[0]],ratio[dirs[2]])/ratio[dirs[2]]", "name": "f2"}, "f1": {"definition": "lcm(ratio[dirs[0]],ratio[dirs[2]])/ratio[dirs[0]]", "name": "f1"}, "total": {"definition": "ratiototal*factor", "name": "total"}, "possibleratios": {"definition": "[1,2,3,4,5,6,7,8]", "name": "possibleratios"}, "prices": {"definition": "map(ratio[j]*factor,j,[0,1,2])", "name": "prices"}, "gcdr": {"definition": "//gcd of r1,r2,r3\n gcd(gcd(r1,r2),r3)", "name": "gcdr"}, "ratiototal": {"definition": "sum(ratio)", "name": "ratiototal"}, "factor": {"definition": "random(12..20)", "name": "factor"}, "ratio": {"definition": "[r1/gcdr,r2/gcdr,r3/gcdr]", "name": "ratio"}}, "metadata": {"notes": "", "description": "Three items of work done on a car. Given total price, and a couple of ratios of prices between pairs of items, work out the cost of one of the items.
\nBased on question 4 from section 3 of the Maths-Aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Numerical reasoning - ratio recipe", "extensions": ["stats"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {"describesol": {"definition": "if(ratios[j]=1,\"$U$ is not more than $\"+u[j]+\"$.\",\"$\"+ratios[j]+\"$ is not more than $\"+u[j]+\"$, i.e. $U$ is not more than $\"+(u[j]/ratios[j])+\"$.\")", "type": "string", "language": "jme", "parameters": [["j", "number"]]}}, "tags": ["chain rule", "proportion", "ratio"], "type": "question", "advice": "The proportions {ratios[0]}:{ratios[1]}:{ratios[2]} have to be preserved.
\nSo if we use $\\simplify{{ratios[0]}*U}$ {units} of $x$ then we must use $\\simplify{{ratios[1]}*U}$ {units} of $y$ and $\\simplify{{ratios[2]}*U}$ {units} of $z$, to get $\\var{ratiototal}U$ {units} of the preparation.
\nWe would like $U$ to be as big as possible.
\nAs we have $\\var{u[0]}$ {units} of $x$, {describesol(0)}
\nAs we have $\\var{u[1]}$ {units} of $y$, {describesol(1)}
\nAs we have $\\var{u[2]}$ {units} of $z$, {describesol(2)}
\nSo the maximum value of $U$ is $\\var{lots}$ and we can make $\\var{lots} \\times \\var{ratiototal} = \\var{amount}$ {units} of the preparation.
", "rulesets": {}, "parts": [{"prompt": "How many {units} of the preparation can be made from a stock of materials consisting of {u[0]} {units} of $x$, {u[1]} {units} of $y$, and {u[2]} {units} of $z$?
\n[[0]] {units}
", "marks": 0, "gaps": [{"marks": 1, "maxValue": "amount", "minValue": "amount", "showCorrectAnswer": true, "scripts": {}, "type": "numberentry", "showPrecisionHint": false}], "showCorrectAnswer": true, "scripts": {}, "type": "gapfill"}], "statement": "A certain preparation consists of liquids $x$, $y$ and $z$ in the proportion {ratios[0]}:{ratios[1]}:{ratios[2]}.
", "variable_groups": [], "progress": "ready", "preamble": {"css": "", "js": ""}, "variables": {"rv": {"definition": "vector(ratios)", "templateType": "anything", "group": "Ungrouped variables", "name": "rv", "description": ""}, "rawratios": {"definition": "shuffle([random(1..7 except 3),random(1..7 except 3),3])", "templateType": "anything", "group": "Ungrouped variables", "name": "rawratios", "description": ""}, "lots": {"definition": "floor(min(map(u[j]/ratios[j],j,0..2)\t))", "templateType": "anything", "group": "Ungrouped variables", "name": "lots", "description": ""}, "uv": {"definition": "vector(u)", "templateType": "anything", "group": "Ungrouped variables", "name": "uv", "description": ""}, "rgcd": {"definition": "gcd(gcd(rawratios[0],rawratios[1]),rawratios[2])", "templateType": "anything", "group": "Ungrouped variables", "name": "rgcd", "description": ""}, "amount": {"definition": "lots*ratiototal", "templateType": "anything", "group": "Ungrouped variables", "name": "amount", "description": ""}, "u": {"definition": "//amount of each liquid\n map(random(3..10)*ratios[j],j,0..2)", "templateType": "anything", "group": "Ungrouped variables", "name": "u", "description": ""}, "ratios": {"definition": "map(rawratios[j]/rgcd,j,0..2)", "templateType": "anything", "group": "Ungrouped variables", "name": "ratios", "description": ""}, "units": {"definition": "random('litres','gallons','millilitres')", "templateType": "anything", "group": "Ungrouped variables", "name": "units", "description": ""}, "ratiototal": {"definition": "sum(ratios)", "templateType": "anything", "group": "Ungrouped variables", "name": "ratiototal", "description": ""}}, "metadata": {"notes": "", "description": "Given ratio of ingredients in a preparation, and amounts of each ingredient, work out how much of the preparation you can make.
\nBased on question 5 from section 3 of the maths-aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Numerical reasoning - percentages and profit", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "functions": {"commanumber": {"definition": "var parts=n.toString().split(\".\");\n return parts[0].replace(/\\B(?=(\\d{3})+(?!\\d))/g, \",\") + (parts[1] ? \".\" + parts[1] : \"\");", "type": "string", "language": "javascript", "parameters": [["n", "number"]]}, "lcommanumber": {"definition": "var parts=n.toString().split(\".\");\n return parts[0].replace(/\\B(?=(\\d{3})+(?!\\d))/g, \",\\\\!\") + (parts[1] ? \".\" + parts[1] : \"\");", "type": "string", "language": "javascript", "parameters": [["n", "number"]]}}, "tags": ["maths-aid", "money", "numerical reasoning", "profit"], "advice": "First, work out the profit made on the original product.
\nThe original production cost was $\\var{produce}$ {pence} per unit. The profit per unit was $\\var{sell}-\\var{produce} = \\var{sell-produce}$ {pence} per unit.
\n{commanumber(units1)} units of the original product were sold per month, so the total profit per month was
\n\\[ \\var{latex(lcommanumber(units1))} \\times \\var{sell-produce} \\var{p} = \\var{latex(lcommanumber(profit1))} \\var{p} = \\var{latex(texpounds)} \\var{latex(lcommanumber(profit1/100))}. \\]
\nNow work out the cost of producing the new product. The new product costs $\\var{percent}\\%$ more. $\\var{percent}\\%$ of $\\var{produce} = \\simplify{{percent}/100}$ of $\\var{produce} = \\var{produce2-produce}\\var{p}$.
\nSo the new production cost is $\\var{produce} + \\var{produce2-produce} = \\var{produce2} \\var{p}$. The profit per unit is now $\\var{sell} - \\var{produce2} = \\var{sell-produce2} \\var{p}$.
\n{commanumber(units2)} units of the new product were sold per month, so the total profit per month is now
\n\\[ \\var{latex(lcommanumber(units2))} \\times \\var{sell-produce2} \\var{p} = \\var{latex(lcommanumber(profit2))} \\var{p} = \\var{latex(texpounds)} \\var{latex(lcommanumber(profit2/100))}. \\]
\nSo the added profit is $\\var{latex(texpounds)}\\var{latex(lcommanumber(profit2/100))} - \\var{latex(texpounds)}\\var{latex(lcommanumber(profit1/100))} = \\var{latex(texpounds)}\\var{latex(lcommanumber(extraprofit))}.$
", "rulesets": {}, "parts": [{"prompt": "If the manufacturer's selling price in each instance was {sell} {pence} per unit, what was the manufacturer's added profit per month with the newer product?
\n{pounds} [[0]]
", "gaps": [{"minvalue": "extraprofit", "type": "numberentry", "maxvalue": "extraprofit", "marks": 1.0, "showPrecisionHint": false}], "type": "gapfill", "marks": 0.0}], "statement": "A product costing {produce} {pence} per unit to produce had been selling at the average rate of {commanumber(units1)} units per month.
\nAfter the product was improved, sales increased to an average of {commanumber(units2)} units per month. However, the new product cost {percent} percent more to produce.
", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"sell": {"definition": "produce+random(20..40#5)", "name": "sell"}, "units1": {"definition": "random(1..15)*mult", "name": "units1"}, "units2": {"definition": "ceil(profit1/(sell-produce2)/mult)*mult+random(1..8)*mult", "name": "units2"}, "produce2": {"definition": "produce*diff", "name": "produce2"}, "pounds": {"definition": "currency[0]", "name": "pounds"}, "texpounds": {"definition": "latex(if(pounds='$','\\\\$',pounds))", "name": "texpounds"}, "percent": {"definition": "(diff-1)*100", "name": "percent"}, "pence": {"definition": "currency[1]", "name": "pence"}, "p": {"definition": "currency[2]", "name": "p"}, "produce": {"definition": "random(40..95#5)", "name": "produce"}, "extraprofit": {"definition": "(profit2-profit1)/100", "name": "extraprofit"}, "diff": {"definition": "random(1.05..floor(20*sell/produce)/20#0.05)", "name": "diff"}, "currency": {"definition": "random(['$','cents','\u00a2'],['\u00a3','pence','p'],['\u20ac','cents','c'])", "name": "currency"}, "profit1": {"definition": "units1*(sell-produce)", "name": "profit1"}, "mult": {"definition": "10^random(3,4,5)", "name": "mult"}, "profit2": {"definition": "ceil(units2*(sell-produce2))", "name": "profit2"}}, "metadata": {"notes": "", "description": "Given cost of production and price of sale of a product; a percentage increase in cost of production; and unit sales before and after; work out the extra profit.
\nBased on question 6 from section 3 of the maths-aid workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}], "pickQuestions": 0}], "type": "exam", "feedback": {"showtotalmark": true, "advicethreshold": 0.0, "showanswerstate": true, "showactualmark": true, "allowrevealanswer": true, "enterreviewmodeimmediately": false, "showexpectedanswerswhen": "never", "showpartfeedbackmessageswhen": "always", "showactualmarkwhen": "always", "showtotalmarkwhen": "always", "showanswerstatewhen": "always", "showadvicewhen": "never"}, "timing": {"timeout": {"action": "none", "message": ""}, "timedwarning": {"action": "none", "message": ""}}, "shufflequestions": false, "questions": [], "percentpass": 0.0, "duration": 0.0, "pickQuestions": 0, "navigation": {"allowregen": true, "browse": true, "onleave": {"action": "none", "message": "You haven't submitted an answer to this question.
"}, "showfrontpage": true, "reverse": true, "showresultspage": "never"}, "showQuestionGroupNames": false, "metadata": {"notes": "", "description": "Based on section 3 of the maths-aid/mathcentre workbook on numerical reasoning.
", "licence": "Creative Commons Attribution 4.0 International"}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}], "extensions": ["stats"], "custom_part_types": [], "resources": []}