PSLE
On Friday, the number of adults to girls to boys visiting a park was 1 : 10 : 10. On Saturday, the number of adults visiting the park remained the same. However, the number of girls decreased by 20% and the number of boys increased by 20%.

1. What was the ratio of the number of children to adults visiting the park on Saturday?
2. On Friday, 980 girls and boys visited the park. What was the total number of child visitors at the park on Saturday?

	Adults	Girls	Boys
Before	1 u	10 u	10 u
Change		- 2 u	+ 2 u
After	1 u	8 u	12 u

(a)
Increase in the number of girls
= 20% x 10 u
= ²⁰₁₀₀ x 10 u
= 2 u

Decrease in the number of boys
= 20% x 10 u
= ²⁰₁₀₀ x 10 u
= 2 u

Number of girls on Saturday
= 10 u - 2 u
= 8 u

Number of boys on Saturday
= 10 u + 2 u
= 12 u

Number of children on Saturday
= 8 u + 12 u
= 20 u

On Saturday
Children : Adults
20 : 1

(b)
Number of girls and boys on Friday
= 10 u + 10 u
= 20 u

20 u = 980

1 u = 980 ÷ 20 = 49

Total number of child visitors on Saturday
= 20 u
= 20 x 49
= 980

Answer(s): (a) 20 : 1; (b) 980