PSLE
On Wednesday, the number of adults to boys to girls visiting a bird park was 5 : 8 : 10. On Thursday, 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 10%.

1. What was the ratio of the number of children to adults visiting the bird park on Thursday?
2. On Wednesday, 414 boys and girls visited the bird park. What was the total number of child visitors at the bird park on Thursday?

	Adults	Boys	Girls
Before	5 u	8 u	10 u
Change		- 4 u	+ 1 u
After	5 u	4 u	11 u

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

Decrease in the number of girls
= 10% x 10 u
= ¹⁰₁₀₀ x 10 u
= 1 u

Number of boys on Thursday
= 8 u - 4 u
= 4 u

Number of girls on Thursday
= 10 u + 1 u
= 11 u

Number of children on Thursday
= 4 u + 11 u
= 15 u

On Thursday
Children : Adults
15 : 5

(b)
Number of boys and girls on Wednesday
= 8 u + 10 u
= 18 u

18 u = 414

1 u = 414 ÷ 18 = 23

Total number of child visitors on Thursday
= 15 u
= 15 x 23
= 345

Answer(s): (a) 15 : 5; (b) 345