PSLE
The students at a sports meet are divided in Team A and Team B. The ratio of the number of girls to boys in Team A is 7 : 5. The ratio of the number of girls to boys in Team B is 5 : 1. There are 2 times as many students in Team B as in Team A. There are 156 less girls in Team A than Team B. What is the total number of students in Team A?

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

Total number of students in Team A
= 7 u + 5 u
= 12 u

Total number of students in Team B
= 2 x 12 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 less girls in Team A than Team B
= 20 u - 7 u
= 13 u

13 u = 156

1 u = 156 ÷ 13 = 12

Total number of students in Team A
= 7 u + 5 u
= 12 u
= 12 x 12
= 144

Answer(s): 144