PSLE
On Wednesday, the number of children to women to men visiting a zoo was 7 : 12 : 6. On Thursday, the number of children visiting the zoo remained the same. However, the number of women decreased by 50% and the number of men increased by 50%.

1. What was the ratio of the number of adults to children visiting the zoo on Thursday?
2. On Wednesday, 666 women and men visited the zoo. What was the total number of adult visitors at the zoo on Thursday?

	Children	Women	Men
Before	7 u	12 u	6 u
Change		- 6 u	+ 3 u
After	7 u	6 u	9 u

(a)
Increase in the number of women
= 50% x 12 u
= ⁵⁰₁₀₀ x 12 u
= 6 u

Decrease in the number of men
= 50% x 6 u
= ⁵⁰₁₀₀ x 6 u
= 3 u

Number of women on Thursday
= 12 u - 6 u
= 6 u

Number of men on Thursday
= 6 u + 3 u
= 9 u

Number of adults on Thursday
= 6 u + 9 u
= 15 u

On Thursday
Adults : Children
15 : 7

(b)
Number of women and men on Wednesday
= 12 u + 6 u
= 18 u

18 u = 666

1 u = 666 ÷ 18 = 37

Total number of adult visitors on Thursday
= 15 u
= 15 x 37
= 555

Answer(s): (a) 15 : 7; (b) 555