PSLE
On Wednesday, the number of adults to boys to girls visiting a museum was 1 : 10 : 10. On Thursday, the number of adults visiting the museum remained the same. However, the number of boys increased by 40% and the number of girls decreased by 10%.

1. What was the ratio of the number of adults to boys to girls visiting the museum on Thursday?
2. On Wednesday, 920 boys and girls visited the museum. What was the total number of visitors at the museum on Thursday?

	Adults	Boys	Girls
Before	1 u	10 u	10 u
Change		+ 4 u	- 1 u
After	1 u	14 u	9 u

(a)
Increase in the number of boys
= 40% x 10 u
= ⁴⁰₁₀₀ x 10 u
= 4 u

Decrease in the number of girls
= 10% x 10 u
= ¹⁰₁₀₀ x 10 u
= 1 u

Number of boys on Thursday
= 10 u + 4 u
= 14 u

Number of girls on Thursday
= 10 u - 1 u
= 9 u

On Thursday
Adults : Boys : Girls
1 : 14 : 9

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

20 u = 920

1 u = 920 ÷ 20 = 46

Total number of visitors on Thursday
= 1 u + 14 u + 9 u
= 24 u
= 24 x 46
= 1104

Answer(s): (a) 1 : 14 : 9; (b) 1104