ExpertMedium3 marksStructured
AQA GCSE · Question 24 · Ratio Proportion and Rates of Change
384 000 electric cars were sold this year. This is 20% more than last year. How many were sold last year?
384 000 electric cars were sold this year. This is 20% more than last year. How many were sold last year?
How to approach this question
1. "20% more than last year" means this year's sales are 100% + 20% = 120% of last year's sales.
2. Convert this percentage to a decimal multiplier: 120% = 1.20.
3. Let L be the number of cars sold last year. The equation is L * 1.20 = 384 000.
4. To find L, we need to do the reverse operation. Divide this year's sales by the multiplier.
5. L = 384 000 / 1.20.
6. Calculate the result: L = 320 000.
Full Answer
This is a reverse percentage problem.
This year's sales are "20% more than last year". This means this year's sales are 100% (last year's amount) + 20% (the increase) = 120% of last year's sales.
So, we can say:
120% of last year's sales = 384 000
To work with this, we convert the percentage to a decimal multiplier:
120% = 120 / 100 = 1.2
Let L be the number of cars sold last year. The equation is:
L × 1.2 = 384 000
To find L, we need to divide 384 000 by 1.2:
L = 384 000 / 1.2
L = 320 000
So, 320 000 electric cars were sold last year.
Common mistakes
✗ The most common mistake is to calculate 20% of 384 000 and subtract it. This is incorrect because the 20% increase was based on last year's smaller number, not this year's larger number. (384000 * 0.8 = 307200 is the wrong answer).
✗ Dividing by 1.2 incorrectly.
Practice the full AQA GCSE Maths Foundation Tier Paper 2 Calculator
45 questions · hints · full answers · grading
More questions from this exam
Q01.1A linear sequence starts: 4, 7, 10, 13. Write down the next number in this sequence.EasyQ01.2A different linear sequence starts: 19, 14, 9, 4. Write down the next number in this sequence.EasyQ01.3Here is another sequence: 3, 6, 12, 24. Write down the term-to-term rule for this sequence.EasyQ02.1Here is a price list. Work out the cost of three candles.EasyQ02.2Sal has £7.50. He wants to buy one soap and one body cream. Does he have enough money to also buy...Easy