PSLE
The contestants at a contest are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 3 : 1. The ratio of the number of boys to girls in Team B is 3 : 2. There are 5 times as many contestants in Team B as in Team A. There are 117 more boys in Team B than Team A. What is the total number of contestants?

Team A		Team B
4 u		5x4 = 20 u
Boys	Girls	Boys	Girls
3 u	1 u	3x4 = 12 u	2x4 = 8 u

Total number of contestants in Team A
= 3 u + 1 u
= 4 u

Total number of contestants in Team B
= 5 x 4 u
= 20 u

The total number of contestants in Team B is repeated.
Use LCM to make the total number of contestants in Team B the same.
LCM of 20 and 5 is 20.

Number of more boys in Team B than Team A
= 12 u - 3 u
= 9 u

9 u = 117

1 u = 117 ÷ 9 = 13

Total number of contestants
= 3 u + 1 u + 12 u + 8 u
= 24 u
= 24 x 13
= 312

Answer(s): 312