AQA · Mathematics · 8300
GCSE Maths: Percentages: of an amount (calc)
Ratio & Proportion · AQA GCSE Maths (8300). Cards are generated from the Corbettmaths textbook exercise, practice questions and answers for Percentages: of an amount (calc) (Corbettmaths Video 235), and every card links back to the exact page it came from. Practice tests generate fresh variations of these questions, so the numbers change every attempt. Source material © Corbettmaths — used with attribution.
18 flashcards · Free to study · No account needed
Study this deck
Preparing your cards…
All questions and answers
Read through the full deck, or practise recalling each answer above.
To find a percentage of an amount using a calculator, what operation do you perform?
Show answer
Multiply the amount by the percentage as a decimal (e.g., for 15% of 80, calculate 80 × 0.15).
If 16% of 150 students are left-handed, how many students are left-handed?
Show answer
24 students (150 × 0.16 = 24)
At a football match with 12,600 fans, 37% are children. How many children attended?
Show answer
4,662 children (12,600 × 0.37 = 4,662)
Donald played 1,200 chess games. He drew 6% and lost 33%. How many games did he win?
Show answer
732 games. He drew 72 and lost 396, so he won 1,200 - 72 - 396 = 732.
Why can't exactly 89% of 80 teachers drive to work?
Show answer
Because 89% of 80 = 71.2, which is not a whole number. You can't have a fractional number of teachers.
To increase an amount by a percentage, what calculation do you perform?
Show answer
Multiply the original amount by (1 + the percentage as a decimal). For example, to increase £2,400 by 9%, calculate £2,400 × 1.09.
A carton contains 540ml. A special offer carton contains an extra 35%. How many millilitres are in the special offer carton?
Show answer
729ml (540 × 1.35 = 729)
A population was 4,580,000 in 2014. By 2024 it increased by 18%. What is the 2024 population?
Show answer
5,404,400 (4,580,000 × 1.18 = 5,404,400)
A car costs £18,750. With an 8% discount paid in 60 monthly instalments, how much is each instalment?
Show answer
£287.50. Discounted price: £18,750 × 0.92 = £17,250. Monthly: £17,250 ÷ 60 = £287.50.
A house worth £340,000 increases by 15% then by a further 9%. What is the total increase in value?
Show answer
£86,190. (First increase: £340,000 × 1.15 = £391,000. Second increase: £391,000 × 1.09 = £426,190. Total increase: £426,190 - £340,000 = £86,190)
If both the length and width of a rectangle are increased by 35%, by what percentage does the area increase?
Show answer
82.25%. The area multiplies by 1.35 × 1.35 = 1.8225, which is an 82.25% increase.
A car needs 50 litres of petrol at 145.9p per litre with a 3% discount voucher. How much does it cost?
Show answer
£70.77. (50 litres × 145.9p = 7295p. With 3% off: 7295p × 0.97 = 7076.15p = £70.77 approx.)
If 88% of 52,852 people are expected to vote, how many people is that?
Show answer
46,510 people (rounded). Calculate 52,852 × 0.88 = 46,509.76.
A hotel has 5,000 guests; 68% are business guests. How many are leisure guests?
Show answer
1,600 leisure guests. (100% - 68% = 32%. 5,000 × 0.32 = 1,600)
A ball drops from 3m and bounces to 80% of the previous height each time. What height after the second bounce?
Show answer
1.92m. (First bounce: 3 × 0.8 = 2.4m. Second bounce: 2.4 × 0.8 = 1.92m)
A house value decreases by 10% then increases by 10%. Is it worth more, less, or the same as the original value?
Show answer
Less. After a 10% decrease and 10% increase, the value is 99% of the original (0.9 × 1.1 = 0.99).
Birthday cards make up 11 parts of a 9:11 ratio. What percentage of total cards are birthday cards?
Show answer
55%. (11 out of 20 total parts: 11/20 = 0.55 = 55%)
A company makes 746,000 cards in ratio 9:11 (Christmas:birthday). 26% of birthday cards have badges. How many birthday cards have no badge?
Show answer
303,820 cards. (Birthday cards: 746,000 × 11/20 = 410,300. Without badge: 410,300 × 0.74 = 303,622)
Want to create your own cards? Create a free account. AI generation uses credits.