PSLE
The number of girls and boys taking part in a quiz are in the ratio 1 : 3. These students are put into two teams. 30% of the girls and 40% of the boys are in Team L. The rest of the students are in Team M.

1. What is the ratio of the number of students in Team M to Team L? Give your answer in the simplest form.
2. The number of boys in Team L is more than 40. What is the smallest possible total number of students taking part in the quiz?

Girls		Boys
10 u		30 u
Team L	Team M	Team L	Team M
3 u	7 u	12 u	18 u

(a)
Girls : Boys
1 : 3
10 : 30

Number of girls in Team L
= 30% x 10 u
= ³⁰₁₀₀ x 10 u
= 3 u

Number of girls in Team M
= 10 u - 3 u
= 7 u

Number of boys in Team L
= 40% x 30 u
= ⁴⁰₁₀₀ x 30 u
= 12 u

Number of boys in Team M
= 30 u - 12 u
= 18 u

Team L : Team M
7 + 18 : 3 + 12 
25 : 15 _(÷5)
5 : 3

(b)
Number of boys in Team L = 12 u

Since the number of boys in Team L is 12 u, it must be multiple of 12.

Number of sets of 12
= 40 ÷ 12
= 3 r 4

Since the number of boys in Team L is more than 40, the number of sets must be 1 more than 3.

1 u = 3 + 1 = 4

Smallest possible number of students
= 10 u + 30 u
= 40 u
= 40 x 4
= 160

Answer(s): (a) 5 : 3; (b) 160