Maths : Ratio QA

Maths : Ratio

1. Write the ratio of 3 apples to 5 apples.

Answer: 3 : 5

Explanation:

Ratio compares quantities of the same type.

So, apples to apples = 3 : 5.

2. Express the ratio 12 : 18 in its simplest form.

Answer: 2 : 3

Explanation:

Find the HCF of 12 and 18, which is 6.

Divide both terms by 6:

12 ÷ 6 = 2, 18 ÷ 6 = 3

So the simplest form is 2 : 3.

3. The ratio of boys to girls in a class is 4 : 5. If there are 20 boys, how many girls are there?

Answer: 25 girls

Explanation:

4 parts = 20 boys

1 part = 20 ÷ 4 = 5

Girls = 5 parts = 5 × 5 = 25

4. Divide ₹120 in the ratio 2 : 3.

Answer: ₹48 and ₹72

Explanation:

Total parts = 2 + 3 = 5

Value of 1 part = 120 ÷ 5 = 24

First share = 2 × 24 = ₹48

Second share = 3 × 24 = ₹72

5. The ratio of red balls to blue balls is 7 : 9. If there are 63 red balls, find the number of blue balls.

Answer: 81 blue balls

Explanation:

7 parts = 63

1 part = 63 ÷ 7 = 9

Blue balls = 9 parts = 9 × 9 = 81

6. The ratio of length to breadth of a rectangle is 5 : 3. If the length is 25 cm, find the breadth.

Answer: 15 cm

Explanation:

5 parts = 25 cm

1 part = 25 ÷ 5 = 5 cm

Breadth = 3 parts = 3 × 5 = 15 cm

7. Two numbers are in the ratio 6 : 11. If their sum is 51, find the two numbers.

Answer: 18 and 33

Explanation:

Total parts = 6 + 11 = 17

1 part = 51 ÷ 17 = 3

First number = 6 × 3 = 18

Second number = 11 × 3 = 33

8. The ages of A and B are in the ratio 3 : 4. If A is 12 years old, find the age of B.

Answer: 16 years

Explanation:

3 parts = 12 years

1 part = 12 ÷ 3 = 4

Age of B = 4 × 4 = 16 years

9. In a bag of marbles, the ratio of green, white, and blue marbles is 2 : 3 : 5. If there are 40 marbles in total, find the number of each color.

Answer:

Green = 8, White = 12, Blue = 20

Explanation:

Total parts = 2 + 3 + 5 = 10

1 part = 40 ÷ 10 = 4

Green = 2 × 4 = 8

White = 3 × 4 = 12

Blue = 5 × 4 = 20

10. The ratio of milk to water in a mixture is 7 : 3. If the mixture contains 21 litres of milk, find the quantity of water.

Answer: 9 litres

Explanation:

7 parts = 21 litres

1 part = 21 ÷ 7 = 3 litres

Water = 3 parts = 3 × 3 = 9 litres