PSLE
On Friday, the number of adults to girls to boys visiting a theme park was 1 : 8 : 5. On Saturday, the number of adults visiting the theme park remained the same. However, the number of girls increased by 25% and the number of boys decreased by 40%.

1. What was the ratio of the number of adults to girls to boys visiting the theme park on Saturday?
2. On Friday, 637 girls and boys visited the theme park. What was the total number of visitors at the theme park on Saturday?

	Adults	Girls	Boys
Before	1 u	8 u	5 u
Change		+ 2 u	- 2 u
After	1 u	10 u	3 u

(a)
Increase in the number of girls
= 25% x 8 u
= ²⁵₁₀₀ x 8 u
= 2 u

Decrease in the number of boys
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u
= 2 u

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

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

On Saturday
Adults : Girls : Boys
1 : 10 : 3

(b)
Number of girls and boys on Friday
= 8 u + 5 u
= 13 u

13 u = 637

1 u = 637 ÷ 13 = 49

Total number of visitors on Saturday
= 1 u + 10 u + 3 u
= 14 u
= 14 x 49
= 686

Answer(s): (a) 1 : 10 : 3; (b) 686