PSLE
The number of girls and boys taking part in a test are in the ratio 3 : 2. These students are put into two teams. 60% of the girls and 10% of the boys are in Team S. The rest of the students are in Team T.

1. What is the ratio of the number of students in Team T to Team S? Give your answer in the simplest form.
2. The number of girls in Team T is fewer than 30. What is the largest possible total number of students taking part in the test?

Girls		Boys
30 u		20 u
Team S	Team T	Team S	Team T
18 u	12 u	2 u	18 u

(a)
Girls : Boys
3 : 2
30 : 20

Number of girls in Team S
= 60% x 30 u
= ⁶⁰₁₀₀ x 30 u
= 18 u

Number of girls in Team T
= 30 u - 18 u
= 12 u

Number of boys in Team S
= 10% x 20 u
= ¹⁰₁₀₀ x 20 u
= 2 u

Number of boys in Team T
= 20 u - 2 u
= 18 u

Team T : Team S
12 + 18 : 18 + 2
30 : 20 _(÷10)
3 : 2

(b)
Number of girls in Team T = 12 u

Since the number of girls in Team T is 12 u, it must be multiple of 12.

Number of sets of 12
= 30 ÷ 12
= 2 r 6

Since the number of girls in Team T is less than 30, the number of sets must be 2.

1 u = 2

Largest possible number of students
= 30 u + 20 u
= 50 u
= 50 x 2
= 100

Answer(s): (a) 3 : 2; (b) 100