PSLE
On Saturday, the number of adults to boys to girls visiting a zoo was 7 : 4 : 10. On Sunday, the number of adults visiting the zoo remained the same. However, the number of boys increased by 25% and the number of girls decreased by 10%.

1. What was the ratio of the number of adults to boys to girls visiting the zoo on Sunday?
2. On Saturday, 294 boys and girls visited the zoo. What was the total number of visitors at the zoo on Sunday?

	Adults	Boys	Girls
Before	7 u	4 u	10 u
Change		+ 1 u	- 1 u
After	7 u	5 u	9 u

(a)
Increase in the number of boys
= 25% x 4 u
= ²⁵₁₀₀ x 4 u
= 1 u

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

Number of boys on Sunday
= 4 u + 1 u
= 5 u

Number of girls on Sunday
= 10 u - 1 u
= 9 u

On Sunday
Adults : Boys : Girls
7 : 5 : 9

(b)
Number of boys and girls on Saturday
= 4 u + 10 u
= 14 u

14 u = 294

1 u = 294 ÷ 14 = 21

Total number of visitors on Sunday
= 7 u + 5 u + 9 u
= 21 u
= 21 x 21
= 441

Answer(s): (a) 7 : 5 : 9; (b) 441