PSLE
The number of boys and girls taking part in a contest are in the ratio 7 : 6. These students are put into two teams. 40% of the boys and 60% of the girls are in Team E. The rest of the students are in Team F.

1. What is the ratio of the number of students in Team F to Team E? Give your answer in the simplest form.
2. The number of girls in Team E is more than 80. What is the smallest possible total number of students taking part in the contest?

Boys		Girls
70 u		60 u
Team E	Team F	Team E	Team F
28 u	42 u	36 u	24 u

(a)
Boys : Girls
7 : 6
70 : 60

Number of boys in Team E
= 40% x 70 u
= ⁴⁰₁₀₀ x 70 u
= 28 u

Number of boys in Team F
= 70 u - 28 u
= 42 u

Number of girls in Team E
= 60% x 60 u
= ⁶⁰₁₀₀ x 60 u
= 36 u

Number of girls in Team F
= 60 u - 36 u
= 24 u

Team E : Team F
42 + 24 : 28 + 36 
66 : 64 _(÷2)
33 : 32

(b)
Number of girls in Team E = 36 u

Since the number of girls in Team E is 36 u, it must be multiple of 36.

Number of sets of 36
= 80 ÷ 36
= 2 r 8

Since the number of girls in Team E is more than 80, the number of sets must be 1 more than 2.

1 u = 2 + 1 = 3

Smallest possible number of students
= 70 u + 60 u
= 130 u
= 130 x 3
= 390

Answer(s): (a) 33 : 32; (b) 390