PSLE
On Thursday, the number of adults to girls to boys visiting a tourist attraction was 7 : 10 : 8. On Friday, the number of adults visiting the tourist attraction remained the same. However, the number of girls increased by 20% and the number of boys decreased by 25%.

1. What was the ratio of the number of adults to girls to boys visiting the tourist attraction on Friday?
2. On Thursday, 468 girls and boys visited the tourist attraction. What was the total number of visitors at the tourist attraction on Friday?

	Adults	Girls	Boys
Before	7 u	10 u	8 u
Change		+ 2 u	- 2 u
After	7 u	12 u	6 u

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

Decrease in the number of boys
= 25% x 8 u
= ²⁵₁₀₀ x 8 u
= 2 u

Number of girls on Friday
= 10 u + 2 u
= 12 u

Number of boys on Friday
= 8 u - 2 u
= 6 u

On Friday
Adults : Girls : Boys
7 : 12 : 6

(b)
Number of girls and boys on Thursday
= 10 u + 8 u
= 18 u

18 u = 468

1 u = 468 ÷ 18 = 26

Total number of visitors on Friday
= 7 u + 12 u + 6 u
= 25 u
= 25 x 26
= 650

Answer(s): (a) 7 : 12 : 6; (b) 650