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 : 3. The ratio of the number of girls to boys in Team B is 7 : 8. There are 3 times as many pupils in Team B as in Team A. There are 84 more girls in Team B than Team A. What is the total number of pupils?

Team A		Team B
10 u		15x2 = 30 u
Girls	Boys	Girls	Boys
7 u	3 u	7x2 = 14 u	8x2 = 16 u

Total number of pupils in Team A
= 7 u + 3 u
= 10 u

Total number of pupils in Team B
= 3 x 10 u
= 30 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 30 and 15 is 30.

Number of more girls in Team B than Team A
= 14 u - 7 u
= 7 u

7 u = 84

1 u = 84 ÷ 7 = 12

Total number of pupils
= 7 u + 3 u + 14 u + 16 u
= 40 u
= 40 x 12
= 480

Answer(s): 480