PSLE
The pupils at a camp 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 : 3. There are 2 times as many pupils in Team B as in Team A. There are 64 more girls in Team B than Team A. What is the total number of pupils?

Team A		Team B
12 u		8x3 = 24 u
Girls	Boys	Girls	Boys
7 u	5 u	5x3 = 15 u	3x3 = 9 u

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

Total number of pupils in Team B
= 2 x 12 u
= 24 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 24 and 8 is 24.

Number of more girls in Team B than Team A
= 15 u - 7 u
= 8 u

8 u = 64

1 u = 64 ÷ 8 = 8

Total number of pupils
= 7 u + 5 u + 15 u + 9 u
= 36 u
= 36 x 8
= 288

Answer(s): 288