PSLE
The students at a sports meet are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 7 : 1. The ratio of the number of boys to girls in Team B is 5 : 1. There are 3 times as many students in Team B as in Team A. There are 52 more boys in Team B than Team A. What is the total number of girls?

Team A		Team B
8 u		6x4 = 24 u
Boys	Girls	Boys	Girls
7 u	1 u	5x4 = 20 u	1x4 = 4 u

Total number of students in Team A
= 7 u + 1 u
= 8 u

Total number of students in Team B
= 3 x 8 u
= 24 u

The total number of students in Team B is repeated.
Use LCM to make the total number of students in Team B the same.
LCM of 24 and 6 is 24.

Number of more boys in Team B than Team A
= 20 u - 7 u
= 13 u

13 u = 52

1 u = 52 ÷ 13 = 4

Total number of girls
= 1 u + 4 u
= 5 u
= 5 x 4
= 20

Answer(s): 20