// Numbas version: exam_results_page_options
{"name": "Lois's copy of Single ball from box", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "ungrouped_variables": ["m", "n", "colour", "AnswerNum"], "name": "Lois's copy of Single ball from box", "tags": ["probability", "Probability", "probability of single event"], "preamble": {"css": "", "js": ""}, "advice": "<p>For any event $A$&nbsp;</p>\n<p>Probability of $A$ = $\\frac{\\text{Number of outcomes for which A happens}} {\\text{Total number of outcomes (sample space)}}$.</p>\n<p></p>\n<p>Let $A$ represent the outcome that the ball selected is $\\var{colour}$, then $P(A) =\\frac{\\var{answernum}}{\\var{m}+\\var{n}}$.</p>\n<p>See <a href=\"https://www.mathsisfun.com/data/probability.html\">https://www.mathsisfun.com/data/probability.html </a>for more information about the topic of probability.</p>\n<p></p>", "rulesets": {}, "parts": [{"prompt": "<p>What is the probability that the ball is $\\var{colour}$?</p>\n<p>Give your answer as a fraction.</p>\n<p>[[0]]</p>", "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "gaps": [{"allowFractions": true, "variableReplacements": [], "maxValue": "{answernum}/({m}+{n})", "minValue": "{answernum}/({m}+{n})", "variableReplacementStrategy": "originalfirst", "correctAnswerFraction": true, "showCorrectAnswer": true, "scripts": {}, "marks": 1, "type": "numberentry", "showPrecisionHint": false}], "showCorrectAnswer": true, "scripts": {}, "marks": 0, "type": "gapfill"}], "extensions": [], "statement": "<p>A box contains&nbsp;<span style=\"font-family: sans-serif; font-size: 16px;\">$\\var{m} $</span>&nbsp;white balls and&nbsp;<span style=\"font-family: sans-serif; font-size: 16px;\">$\\var{n} $</span>&nbsp;black balls. A ball is drawn out of the box at random.&nbsp;</p>", "variable_groups": [], "variablesTest": {"maxRuns": 100, "condition": ""}, "variables": {"colour": {"definition": "random('black', 'white')", "templateType": "anything", "group": "Ungrouped variables", "name": "colour", "description": "<p>The colour asked for in the question.</p>"}, "AnswerNum": {"definition": "if(colour = 'white',m,n)", "templateType": "anything", "group": "Ungrouped variables", "name": "AnswerNum", "description": ""}, "m": {"definition": "random(3..7)", "templateType": "anything", "group": "Ungrouped variables", "name": "m", "description": "<p>The number of white balls in the box.</p>"}, "n": {"definition": "random(3..13)", "templateType": "anything", "group": "Ungrouped variables", "name": "n", "description": "<p>The number of black balls in the box.</p>"}}, "metadata": {"description": "<p>A box contains $m$ white balls and $n$ black balls. A ball is drawn out of the box at random. What is the probability that the ball is black/white?</p>", "licence": "Creative Commons Attribution 4.0 International"}, "type": "question", "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}], "contributors": [{"name": "Lois Rollings", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/326/"}]}]}], "contributors": [{"name": "Lois Rollings", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/326/"}]}