PSLE
The number of boys and girls taking part in a test are in the ratio 3 : 4. These students are put into two teams. 20% of the boys and 50% of the girls are in Team H. The rest of the students are in Team J.

1. What is the ratio of the number of students in Team J to Team H? Give your answer in the simplest form.
2. The number of boys in Team J is fewer than 50. What is the largest possible total number of students taking part in the test?

Boys		Girls
30 u		40 u
Team H	Team J	Team H	Team J
6 u	24 u	20 u	20 u

(a)
Boys : Girls
3 : 4
30 : 40

Number of boys in Team H
= 20% x 30 u
= ²⁰₁₀₀ x 30 u
= 6 u

Number of boys in Team J
= 30 u - 6 u
= 24 u

Number of girls in Team H
= 50% x 40 u
= ⁵⁰₁₀₀ x 40 u
= 20 u

Number of girls in Team J
= 40 u - 20 u
= 20 u

Team J : Team H
24 + 20 : 6 + 20
44 : 26 _(÷2)
22 : 13

(b)
Number of boys in Team J = 24 u

Since the number of boys in Team J is 24 u, it must be multiple of 24.

Number of sets of 24
= 50 ÷ 24
= 2 r 2

Since the number of boys in Team J is less than 50, the number of sets must be 2.

1 u = 2

Largest possible number of students
= 30 u + 40 u
= 70 u
= 70 x 2
= 140

Answer(s): (a) 22 : 13; (b) 140