PSLE
The contestants at a contest are divided in Team A and Team B. The ratio of the number of girls to boys in Team A is 3 : 2. The ratio of the number of girls to boys in Team B is 9 : 1. There are 4 times as many contestants in Team B as in Team A. There are 60 less girls in Team A than Team B. What is the total number of contestants in Team A?

Team A		Team B
5 u		10x2 = 20 u
Girls	Boys	Girls	Boys
3 u	2 u	9x2 = 18 u	1x2 = 2 u

Total number of contestants in Team A
= 3 u + 2 u
= 5 u

Total number of contestants in Team B
= 4 x 5 u
= 20 u

The total number of contestants in Team B is repeated.
Use LCM to make the total number of contestants in Team B the same.
LCM of 20 and 10 is 20.

Number of less girls in Team A than Team B
= 18 u - 3 u
= 15 u

15 u = 60

1 u = 60 ÷ 15 = 4

Total number of contestants in Team A
= 3 u + 2 u
= 5 u
= 5 x 4
= 20

Answer(s): 20