PSLE
The pupils at a school choir are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 3 : 2. The ratio of the number of boys to girls in Team B is 2 : 1. There are 3 times as many pupils in Team B as in Team A. There are 56 more boys in Team B than Team A. What is the total number of girls?

Team A		Team B
5 u		3x5 = 15 u
Boys	Girls	Boys	Girls
3 u	2 u	2x5 = 10 u	1x5 = 5 u

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

Total number of pupils in Team B
= 3 x 5 u
= 15 u

The total number of pupils in Team B is repeated.
Use LCM to make the total number of pupils in Team B the same.
LCM of 15 and 3 is 15.

Number of more boys in Team B than Team A
= 10 u - 3 u
= 7 u

7 u = 56

1 u = 56 ÷ 7 = 8

Total number of girls
= 2 u + 5 u
= 7 u
= 7 x 8
= 56

Answer(s): 56