PSLE
The number of girls and boys taking part in a quiz are in the ratio 5 : 8. These students are put into two teams. 40% of the girls and 10% of the boys are in Team A. The rest of the students are in Team B.

1. What is the ratio of the number of students in Team B to Team A? Give your answer in the simplest form.
2. The number of girls in Team B is fewer than 80. What is the largest possible total number of students taking part in the quiz?

Girls		Boys
50 u		80 u
Team A	Team B	Team A	Team B
20 u	30 u	8 u	72 u

(a)
Girls : Boys
5 : 8
50 : 80

Number of girls in Team A
= 40% x 50 u
= ⁴⁰₁₀₀ x 50 u
= 20 u

Number of girls in Team B
= 50 u - 20 u
= 30 u

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

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

Team B : Team A
30 + 72 : 20 + 8
102 : 28 _(÷2)
51 : 14

(b)
Number of girls in Team B = 30 u

Since the number of girls in Team B is 30 u, it must be multiple of 30.

Number of sets of 30
= 80 ÷ 30
= 2 r 20

Since the number of girls in Team B is less than 80, the number of sets must be 2.

1 u = 2

Largest possible number of students
= 50 u + 80 u
= 130 u
= 130 x 2
= 260

Answer(s): (a) 51 : 14; (b) 260