PSLE
On Tuesday, the number of adults to boys to girls visiting a park was 7 : 8 : 5. On Wednesday, the number of adults visiting the park remained the same. However, the number of boys increased by 50% and the number of girls decreased by 20%.

1. What was the ratio of the number of adults to boys to girls visiting the park on Wednesday?
2. On Tuesday, 572 boys and girls visited the park. What was the total number of visitors at the park on Wednesday?

	Adults	Boys	Girls
Before	7 u	8 u	5 u
Change		+ 4 u	- 1 u
After	7 u	12 u	4 u

(a)
Increase in the number of boys
= 50% x 8 u
= ⁵⁰₁₀₀ x 8 u
= 4 u

Decrease in the number of girls
= 20% x 5 u
= ²⁰₁₀₀ x 5 u
= 1 u

Number of boys on Wednesday
= 8 u + 4 u
= 12 u

Number of girls on Wednesday
= 5 u - 1 u
= 4 u

On Wednesday
Adults : Boys : Girls
7 : 12 : 4

(b)
Number of boys and girls on Tuesday
= 8 u + 5 u
= 13 u

13 u = 572

1 u = 572 ÷ 13 = 44

Total number of visitors on Wednesday
= 7 u + 12 u + 4 u
= 23 u
= 23 x 44
= 1012

Answer(s): (a) 7 : 12 : 4; (b) 1012