PSLE
On Friday, the number of adults to girls to boys visiting a theme park was 3 : 8 : 12. On Saturday, the number of adults visiting the theme park remained the same. However, the number of girls decreased by 50% and the number of boys increased by 50%.

1. What was the ratio of the number of children to adults visiting the theme park on Saturday?
2. On Friday, 660 girls and boys visited the theme park. What was the total number of child visitors at the theme park on Saturday?

	Adults	Girls	Boys
Before	3 u	8 u	12 u
Change		- 4 u	+ 6 u
After	3 u	4 u	18 u

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

Decrease in the number of boys
= 50% x 12 u
= ⁵⁰₁₀₀ x 12 u
= 6 u

Number of girls on Saturday
= 8 u - 4 u
= 4 u

Number of boys on Saturday
= 12 u + 6 u
= 18 u

Number of children on Saturday
= 4 u + 18 u
= 22 u

On Saturday
Children : Adults
22 : 3

(b)
Number of girls and boys on Friday
= 8 u + 12 u
= 20 u

20 u = 660

1 u = 660 ÷ 20 = 33

Total number of child visitors on Saturday
= 22 u
= 22 x 33
= 726

Answer(s): (a) 22 : 3; (b) 726