PSLE
The number of girls and boys taking part in a contest are in the ratio 1 : 8. These pupils are put into two teams. 60% of the girls and 20% of the boys are in Team E. The rest of the pupils are in Team F.

1. What is the ratio of the number of pupils in Team F to Team E? Give your answer in the simplest form.
2. The number of girls in Team F is fewer than 50. What is the largest possible total number of pupils taking part in the contest?

Girls		Boys
10 u		80 u
Team E	Team F	Team E	Team F
6 u	4 u	16 u	64 u

(a)
Girls : Boys
1 : 8
10 : 80

Number of girls in Team E
= 60% x 10 u
= ⁶⁰₁₀₀ x 10 u
= 6 u

Number of girls in Team F
= 10 u - 6 u
= 4 u

Number of boys in Team E
= 20% x 80 u
= ²⁰₁₀₀ x 80 u
= 16 u

Number of boys in Team F
= 80 u - 16 u
= 64 u

Team F : Team E
4 + 64 : 6 + 16
68 : 22 _(÷2)
34 : 11

(b)
Number of girls in Team F = 4 u

Since the number of girls in Team F is 4 u, it must be multiple of 4.

Number of sets of 4
= 50 ÷ 4
= 12 r 2

Since the number of girls in Team F is less than 50, the number of sets must be 12.

1 u = 12

Largest possible number of pupils
= 10 u + 80 u
= 90 u
= 90 x 12
= 1080

Answer(s): (a) 34 : 11; (b) 1080