Welcome to our KS3 Maths Quiz on Percentages, Ratios, and Proportion! The purpose of this quiz is to assess your skills and understanding while providing a fun and engaging experience. Armed with your innate intelligence and skills you've learned in class, you're perfectly equipped to tackle these questions. Let's embark on a math-tastic adventure. Here we go, let's crunch those numbers!

1.

In a class of 30 students, 12 are boys. What is the proportion of boys to girls in the class?

2:5

3:2

2:3

4:3

The number of girls in the class is 30 - 12 = 18. The proportion of boys to girls can be formed by reducing the ratio 12:18 to its simplest form which is 2:3.

2.

In a test Sally scores 42 out of 60 . What is her score as a percentage?

70%

60%

75%

80%

The percentage score can be calculated as (42 ÷ 60) x 100% = 70%.

3.

A bag contains 5 green, 7 red and 3 yellow balls. What is the ratio of green to total balls?

5:15

1:2

5:7

5:20

Total balls = 5 + 7 + 3 = 15. The ratio of green to total balls is 5:15. I hope you didn't work out green to only red and yellow!

4.

Your bank account contains £2,000. If it grows by 5% each year, how much will you have after one year?

£2,100

£2,050

£2,200

£2,150

Find 5% of £2,000 by multiplying, 2,000 x 5 ÷ 100 = £100. Add this to the original amount to get £2,100.

5.

What is the proportion of 3 out of 15 expressed as a percentage?

20%

15%

25%

18%

The proportion of 3 out of 15 can be calculated as (3 ÷ 15) x 100% = 20%.

6.

What is 45% of £250?

£112

£112.50

£125

£140

Find 45% of £250 by multiplying, 250 x 45 ÷ 100 = £112.50

7.

John is 16 years old and Steven is 24 years old. What is their age ratio?

2:3

1:2

3:4

4:6

The age ratio is obtained by dividing both ages by their greatest common divisor which is 8, so the ratio is 2:3.

8.

A group of friends shares a pizza. Fred eats ^{1}⁄_{4} of the pizza, Sam eats ^{1}⁄_{5} and the rest is eaten by Lucy. What fraction of the pizza does Lucy eat?

Fred and Sam eat ^{1}⁄_{4} + ^{1}⁄_{5} = (^{5}⁄_{20} + ^{4}⁄_{20}) = ^{9}⁄_{20} of the pizza. So, Lucy eats ^{11}⁄_{20} (1 - ^{9}⁄_{20}) of the pizza.

9.

A recipe says to mix 2kg of flour with 500g sugar in the ratio 4:1. How much sugar is required for 1kg of flour?

500 g

250 g

400 g

350 g

Since the ratio between flour and sugar is 4:1, 1kg of flour should be mixed with a quarter the weight of sugar, which is 250g.

10.

If a shirt is on sale for 20% off and the original price is £35, what is the new price?

£28

£25

£32

£29

Find 20% of £35 by multiplying, 35 x 20 ÷ 100 = £7. Deduct this from the original price of £35 to get £28.