PSLE
On Thursday, the number of adults to boys to girls visiting a fun fair was 5 : 5 : 4. On Friday, the number of adults visiting the fun fair remained the same. However, the number of boys increased by 40% and the number of girls decreased by 25%.

1. What was the ratio of the number of adults to boys to girls visiting the fun fair on Friday?
2. On Thursday, 333 boys and girls visited the fun fair. What was the total number of visitors at the fun fair on Friday?

	Adults	Boys	Girls
Before	5 u	5 u	4 u
Change		+ 2 u	- 1 u
After	5 u	7 u	3 u

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

Decrease in the number of girls
= 25% x 4 u
= ²⁵₁₀₀ x 4 u
= 1 u

Number of boys on Friday
= 5 u + 2 u
= 7 u

Number of girls on Friday
= 4 u - 1 u
= 3 u

On Friday
Adults : Boys : Girls
5 : 7 : 3

(b)
Number of boys and girls on Thursday
= 5 u + 4 u
= 9 u

9 u = 333

1 u = 333 ÷ 9 = 37

Total number of visitors on Friday
= 5 u + 7 u + 3 u
= 15 u
= 15 x 37
= 555

Answer(s): (a) 5 : 7 : 3; (b) 555