Higher November 2020 Paper 5 Q12

OCRHigherCurrent spec7 marksPercentages

12 The price, £\(P\), of a car is £20 000 in 2019.
The price is expected to decrease by 5% each year after 2019.

(a) Jasmine says

This means the price in 2021 is expected to be £18 000.

She is incorrect.
Explain her error and work out the correct answer. [4]

(b)

(i) Write a formula for \(P\) in terms of \(n\), where \(n\) is the number of years after 2019. [2]

(ii) Circle the graph that best represents the price, £\(P\), of the car \(n\) years after 2019.

[1]

Mark scheme (a)

Answer	Marks	Part marks and guidance
She has reduced the price by 10% oe	B1		e.g. She has decreased by 1000 each year She took 10%/ found 90% [of 20 000] See AG
18 050	B3	M2 for 20 000 × 0.95² oe or B1 for 1000 or 19 000 seen

Response	Mark
She kept decreasing by 5% of 20000	1
She took off the same amount of interest as the first year	1
She should not decrease by the same amount each year [ it should be different]	1
She did simple interest rather than compound interest	1
She is decreasing by the same amount each year	1
She did not do 5% of the second year, just 5% of the first year	1
She took £1000 off each year	1
She should have done 5% for each year	1
She did not decrease the result of the first price (she did by 1000)	0
She has just decreased it by 5% each year	0