PSLE
The pupils at a camp are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 7 : 5. The ratio of the number of boys to girls in Team B is 7 : 1. There are 2 times as many pupils in Team B as in Team A. There are 112 less boys in Team A than Team B. What is the total number of pupils in Team A?

Team A		Team B
12 u		8x3 = 24 u
Boys	Girls	Boys	Girls
7 u	5 u	7x3 = 21 u	1x3 = 3 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 less boys in Team A than Team B
= 21 u - 7 u
= 14 u

14 u = 112

1 u = 112 ÷ 14 = 8

Total number of pupils in Team A
= 7 u + 5 u
= 12 u
= 12 x 8
= 96

Answer(s): 96