PSLE
On Monday, the number of adults to boys to girls visiting a bird park was 7 : 2 : 8. On Tuesday, the number of adults visiting the bird park remained the same. However, the number of boys decreased by 50% and the number of girls increased by 50%.

1. What was the ratio of the number of children to adults visiting the bird park on Tuesday?
2. On Monday, 340 boys and girls visited the bird park. What was the total number of child visitors at the bird park on Tuesday?

	Adults	Boys	Girls
Before	7 u	2 u	8 u
Change		- 1 u	+ 4 u
After	7 u	1 u	12 u

(a)
Increase in the number of boys
= 50% x 2 u
= ⁵⁰₁₀₀ x 2 u
= 1 u

Decrease in the number of girls
= 50% x 8 u
= ⁵⁰₁₀₀ x 8 u
= 4 u

Number of boys on Tuesday
= 2 u - 1 u
= 1 u

Number of girls on Tuesday
= 8 u + 4 u
= 12 u

Number of children on Tuesday
= 1 u + 12 u
= 13 u

On Tuesday
Children : Adults
13 : 7

(b)
Number of boys and girls on Monday
= 2 u + 8 u
= 10 u

10 u = 340

1 u = 340 ÷ 10 = 34

Total number of child visitors on Tuesday
= 13 u
= 13 x 34
= 442

Answer(s): (a) 13 : 7; (b) 442