PSLE
The number of boys and girls taking part in a test are in the ratio 8 : 3. These students are put into two teams. 10% of the boys and 20% of the girls are in Team T. The rest of the students are in Team U.

1. What is the ratio of the number of students in Team U to Team T? Give your answer in the simplest form.
2. The number of girls in Team T is more than 50. What is the smallest possible total number of students taking part in the test?

Boys		Girls
80 u		30 u
Team T	Team U	Team T	Team U
8 u	72 u	6 u	24 u

(a)
Boys : Girls
8 : 3
80 : 30

Number of boys in Team T
= 10% x 80 u
= ¹⁰₁₀₀ x 80 u
= 8 u

Number of boys in Team U
= 80 u - 8 u
= 72 u

Number of girls in Team T
= 20% x 30 u
= ²⁰₁₀₀ x 30 u
= 6 u

Number of girls in Team U
= 30 u - 6 u
= 24 u

Team T : Team U
72 + 24 : 8 + 6 
96 : 14 _(÷2)
48 : 7

(b)
Number of girls in Team T = 6 u

Since the number of girls in Team T is 6 u, it must be multiple of 6.

Number of sets of 6
= 50 ÷ 6
= 8 r 2

Since the number of girls in Team T is more than 50, the number of sets must be 1 more than 8.

1 u = 8 + 1 = 9

Smallest possible number of students
= 80 u + 30 u
= 110 u
= 110 x 9
= 990

Answer(s): (a) 48 : 7; (b) 990