PSLE
On Monday, the number of adults to boys to girls visiting a fun fair was 3 : 5 : 5. On Tuesday, the number of adults visiting the fun fair remained the same. However, the number of boys decreased by 40% and the number of girls increased by 20%.

1. What was the ratio of the number of children to adults visiting the fun fair on Tuesday?
2. On Monday, 350 boys and girls visited the fun fair. What was the total number of child visitors at the fun fair on Tuesday?

	Adults	Boys	Girls
Before	3 u	5 u	5 u
Change		- 2 u	+ 1 u
After	3 u	3 u	6 u

(a)
Increase in the number of boys
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u
= 2 u

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

Number of boys on Tuesday
= 5 u - 2 u
= 3 u

Number of girls on Tuesday
= 5 u + 1 u
= 6 u

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

On Tuesday
Children : Adults
9 : 3

(b)
Number of boys and girls on Monday
= 5 u + 5 u
= 10 u

10 u = 350

1 u = 350 ÷ 10 = 35

Total number of child visitors on Tuesday
= 9 u
= 9 x 35
= 315

Answer(s): (a) 9 : 3; (b) 315