PSLE
The number of girls and boys taking part in a quiz are in the ratio 1 : 4. These pupils are put into two teams. 20% of the girls and 30% of the boys are in Team L. The rest of the pupils are in Team M.

1. What is the ratio of the number of pupils in Team M to Team L? Give your answer in the simplest form.
2. The number of girls in Team M is fewer than 70. What is the largest possible total number of pupils taking part in the quiz?

Girls		Boys
10 u		40 u
Team L	Team M	Team L	Team M
2 u	8 u	12 u	28 u

(a)
Girls : Boys
1 : 4
10 : 40

Number of girls in Team L
= 20% x 10 u
= ²⁰₁₀₀ x 10 u
= 2 u

Number of girls in Team M
= 10 u - 2 u
= 8 u

Number of boys in Team L
= 30% x 40 u
= ³⁰₁₀₀ x 40 u
= 12 u

Number of boys in Team M
= 40 u - 12 u
= 28 u

Team M : Team L
8 + 28 : 2 + 12
36 : 14 _(÷2)
18 : 7

(b)
Number of girls in Team M = 8 u

Since the number of girls in Team M is 8 u, it must be multiple of 8.

Number of sets of 8
= 70 ÷ 8
= 8 r 6

Since the number of girls in Team M is less than 70, the number of sets must be 8.

1 u = 8

Largest possible number of pupils
= 10 u + 40 u
= 50 u
= 50 x 8
= 400

Answer(s): (a) 18 : 7; (b) 400