PSLE
On Friday, the number of adults to girls to boys visiting a zoo was 7 : 8 : 4. On Saturday, the number of adults visiting the zoo remained the same. However, the number of girls increased by 50% and the number of boys decreased by 25%.

1. What was the ratio of the number of adults to girls to boys visiting the zoo on Saturday?
2. On Friday, 384 girls and boys visited the zoo. What was the total number of visitors at the zoo on Saturday?

	Adults	Girls	Boys
Before	7 u	8 u	4 u
Change		+ 4 u	- 1 u
After	7 u	12 u	3 u

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

Decrease in the number of boys
= 25% x 4 u
= ²⁵₁₀₀ x 4 u
= 1 u

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

Number of boys on Saturday
= 4 u - 1 u
= 3 u

On Saturday
Adults : Girls : Boys
7 : 12 : 3

(b)
Number of girls and boys on Friday
= 8 u + 4 u
= 12 u

12 u = 384

1 u = 384 ÷ 12 = 32

Total number of visitors on Saturday
= 7 u + 12 u + 3 u
= 22 u
= 22 x 32
= 704

Answer(s): (a) 7 : 12 : 3; (b) 704