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Try to answer the following questions here:

  • What is this question used for?
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Checkpoint description

Describe what's changed since the last checkpoint.

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Chris Graham 2 years, 2 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).

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Chris Graham 2 years, 2 months ago

Gave some feedback: Ready to use

Elliott Fletcher 2 years, 2 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).

Restore this checkpoint

Elliott Fletcher 2 years, 2 months ago

Gave some feedback: Needs to be tested

Picture of Chris Graham

Chris Graham 2 years, 2 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.

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Chris Graham 2 years, 2 months ago

Gave some feedback: Has some problems

Stanislav Duris 2 years, 2 months ago

Published this.

Stanislav Duris 2 years, 2 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:

  1. At first, a random number from 6 to 9 is picked (testn).
  2. Then pricee1 is calculated, which is the smartphone's value after testn months.
  3. Threshold is calculated, which is the crucial number in the question. This is the first multiple of ten higher than pricee1.
  4. 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.
  5. We calculate the smartphone's value after testn-1 months, this is pricee2.
  6. 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.

Restore this checkpoint

Stanislav Duris 2 years, 2 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 2 years, 2 months ago

Gave some feedback: Needs to be tested

Stanislav Duris 2 years, 2 months ago

Gave some feedback: Has some problems

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Christian Lawson-Perfect 2 years, 2 months ago

Gave some feedback: Has some problems

Picture of Christian Lawson-Perfect

Christian Lawson-Perfect 2 years, 2 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.

Restore this checkpoint

Stanislav Duris 2 years, 2 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 2 years, 2 months ago

Gave some feedback: Needs to be tested

Vicky Hall 2 years, 2 months ago

Gave some feedback: Has some problems

Vicky Hall 2 years, 2 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 2 years, 2 months ago

Gave some feedback: Needs to be tested

Stanislav Duris 2 years, 2 months ago

Created this as a copy of Simple interest.
Name Status Author Last Modified
Simple interest Ready to use Stanislav Duris 14/08/2017 11:57
Cumulative percent decrease Ready to use Stanislav Duris 22/08/2017 14:23
Exponential increase Ready to use Stanislav Duris 01/08/2017 12:03
Ida's copy of Cumulative percent decrease draft Ida Landgärds 12/04/2018 10:54
Spørsmål 4 draft Ida Landgärds 09/01/2019 14:42
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

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