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Given the original price of a smartphone and the rate at which it decreases, calculate its price after a given number of months. In the second part, calculate the time remaining until the price goes below a certain point.
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England schools
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England university
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Scotland schools
Taxonomy: mathcentre
Taxonomy: Kind of activity
Taxonomy: Context
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From users who are members of Transition to university :
Chris Graham
|
said | Ready to use | 7 years, 8 months ago |
| Elliott Fletcher | said | Needs to be tested | 7 years, 8 months ago |
| Stanislav Duris | said | Needs to be tested | 7 years, 8 months ago |
Christian Lawson-Perfect
|
said | Has some problems | 7 years, 8 months ago |
| Vicky Hall | said | Has some problems | 7 years, 8 months ago |
History
Chris Graham commented 7 years, 8 months ago
I've rewritten large parts of the advice, especially where visibility conditions were used, and utilised the random names extension to add some context to part b).
Chris Graham 7 years, 8 months ago
Gave some feedback: Ready to use
Elliott Fletcher 7 years, 8 months ago
Saved a checkpoint:
I have rewritten the step so that it includes the variables in the question and gaps asking the student to calculate the decimal multiplier for the decrease and the value after the first month and then after another month.
I have also added a precision hint for the answer in part a).
Elliott Fletcher 7 years, 8 months ago
Gave some feedback: Needs to be tested
Chris Graham commented 7 years, 8 months ago
This step could be specific to the question variables and gaps, perhaps asking for the decimal multiplier for the decrease, and then the first two month.
There are no precision hints given, though the students need to round to 2 decimal places.
Chris Graham 7 years, 8 months ago
Gave some feedback: Has some problems
Stanislav Duris 7 years, 8 months ago
Published this.Stanislav Duris 7 years, 8 months ago
Saved a checkpoint:
I hope this question won't need more huge adjustments, especially in part b, cause this part's advice was quite tricky to write and the answer is a bit tricky to calculate. I'll try to describe how the answer to part b) works:
- At first, a random number from 6 to 9 is picked (testn).
- Then pricee1 is calculated, which is the smartphone's value after testn months.
- Threshold is calculated, which is the crucial number in the question. This is the first multiple of ten higher than pricee1.
- We would normally be finished, but the numbers and percentages are not big enough so sometimes the decrease in the smartphone's value is less than 10, which means the smarphone's value one month before testn months may also be below threshold.
- We calculate the smartphone's value after testn-1 months, this is pricee2.
- Finally, the correct answer is the variable n. This is either testn-1, if pricee2 < threshold, or testn, if pricee2 > threshold.
Right now, pricee3 (the value after testn-2 months) never falls below the threshold (thank god) so it is not used in the question at all. However, if there'll be some adjustments to the price or the percentages in the question, this may not be true anymore. Make sure it is still ALWAYS below the threshold and if not, adjust the variable "n" so sometimes it can also be testn-2. I hope this is not too confusing and if it is, I hope no one has to deal with this anymore.
Stanislav Duris commented 7 years, 8 months ago
I have changed the part b) how you suggested so it's more natural. I have also separated part c) into its own question.
Stanislav Duris 7 years, 8 months ago
Gave some feedback: Needs to be tested
Stanislav Duris 7 years, 8 months ago
Gave some feedback: Has some problems
Christian Lawson-Perfect 7 years, 8 months ago
Gave some feedback: Has some problems
Christian Lawson-Perfect 7 years, 8 months ago
Saved a checkpoint:
Numbers in text should be in LaTeX, unless they're counting numbers, e.g. "two things". It's conventional to use words instead of digits when you're talking about a number of things or an ordinal, rather than a measurement. See this page from the BBC's style guide.
I've done some rewording in part a, and removed the statement - it was superfluous.
Part b is very artificial. A more natural question would be "after how many more months will the price fall below £xxx?", where the price is a multiple of £10.
Part c could be a separate question.
Stanislav Duris commented 7 years, 8 months ago
I've reworded the statement. I've also made all numbers display in LaTeX, but I am unsure about this, because I have been previously told not to do this for all numbers in text. How do we decide which numbers/variables to put in Latex and which ones to keep as text?
Stanislav Duris 7 years, 8 months ago
Gave some feedback: Needs to be tested
Vicky Hall 7 years, 8 months ago
Gave some feedback: Has some problems
Vicky Hall commented 7 years, 8 months ago
Make sure all number are in Latex. I think the statement needs changing
Check your tenses. For example, 'How much is it worth after 5 months?' would read much better as 'How much will it be worth after 5 months?'. Also, 'After how many more months is the smartphone's value going to be £511.19?' would be better as 'After how many more months will the smartphone's value be £511.19?'.
In part c), I would say leave out the word 'exponentially' and change the next sentence to say 'What was the average percentage increase per year?'.
Stanislav Duris 7 years, 8 months ago
Gave some feedback: Needs to be tested
Stanislav Duris 7 years, 8 months ago
Created this as a copy of Simple interest.| Name | Status | Author | Last Modified | |
|---|---|---|---|---|
| Simple interest | Ready to use | Stanislav Duris | 20/11/2019 14:42 | |
| Cumulative percent decrease | Ready to use | Stanislav Duris | 20/11/2019 14:36 | |
| Exponential increase | Ready to use | Stanislav Duris | 20/11/2019 14:38 | |
| Ida's copy of Cumulative percent decrease | draft | Ida Landgärds | 12/04/2018 10:54 | |
| Spørsmål 4 | draft | Ida Landgärds | 02/12/2020 15:42 | |
| haifa's copy of Cumulative percent decrease | draft | haifa abd | 01/05/2018 14:20 | |
| Consumer Arithmetic - Simple Interest | draft | Paul Hancock | 24/07/2018 03:08 |
There are 9 other versions that do you not have access to.
| Name | Type | Generated Value |
|---|
| price | number |
301.99
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| perc | number |
4
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| Name | Type | Generated Value |
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| threshold | number |
230
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| pricee1 | number |
226.93
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| pricee2 | number |
236.39
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| pricee3 | number |
246.23
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| testn | integer |
7
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| test | number |
226.93
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| price2 | number |
226.93
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| n | integer |
7
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| person | dict |
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|---|
Generated value: number
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