PSLE
The number of girls and boys taking part in a test are in the ratio 1 : 5. These students are put into two teams. 40% of the girls and 20% of the boys are in Team D. The rest of the students are in Team E.

1. What is the ratio of the number of students in Team E to Team D? Give your answer in the simplest form.
2. The number of girls in Team E is fewer than 40. What is the largest possible total number of students taking part in the test?

Girls		Boys
10 u		50 u
Team D	Team E	Team D	Team E
4 u	6 u	10 u	40 u

(a)
Girls : Boys
1 : 5
10 : 50

Number of girls in Team D
= 40% x 10 u
= ⁴⁰₁₀₀ x 10 u
= 4 u

Number of girls in Team E
= 10 u - 4 u
= 6 u

Number of boys in Team D
= 20% x 50 u
= ²⁰₁₀₀ x 50 u
= 10 u

Number of boys in Team E
= 50 u - 10 u
= 40 u

Team E : Team D
6 + 40 : 4 + 10
46 : 14 _(÷2)
23 : 7

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

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

Number of sets of 6
= 40 ÷ 6
= 6 r 4

Since the number of girls in Team E is less than 40, the number of sets must be 6.

1 u = 6

Largest possible number of students
= 10 u + 50 u
= 60 u
= 60 x 6
= 360

Answer(s): (a) 23 : 7; (b) 360