PSLE
On Monday, the number of adults to girls to boys visiting a bird park was 7 : 6 : 2. On Tuesday, the number of adults visiting the bird park remained the same. However, the number of girls increased by 50% and the number of boys decreased by 50%.

1. What was the ratio of the number of adults to girls to boys visiting the bird park on Tuesday?
2. On Monday, 184 girls and boys visited the bird park. What was the total number of visitors at the bird park on Tuesday?

	Adults	Girls	Boys
Before	7 u	6 u	2 u
Change		+ 3 u	- 1 u
After	7 u	9 u	1 u

(a)
Increase in the number of girls
= 50% x 6 u
= ⁵⁰₁₀₀ x 6 u
= 3 u

Decrease in the number of boys
= 50% x 2 u
= ⁵⁰₁₀₀ x 2 u
= 1 u

Number of girls on Tuesday
= 6 u + 3 u
= 9 u

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

On Tuesday
Adults : Girls : Boys
7 : 9 : 1

(b)
Number of girls and boys on Monday
= 6 u + 2 u
= 8 u

8 u = 184

1 u = 184 ÷ 8 = 23

Total number of visitors on Tuesday
= 7 u + 9 u + 1 u
= 17 u
= 17 x 23
= 391

Answer(s): (a) 7 : 9 : 1; (b) 391