PSLE
The contestants at a contest are divided in Team A and Team B. The ratio of the number of girls to boys in Team A is 7 : 1. The ratio of the number of girls to boys in Team B is 11 : 1. There are 3 times as many contestants in Team B as in Team A. There are 150 more girls in Team B than Team A. What is the total number of contestants?

Team A		Team B
8 u		12x2 = 24 u
Girls	Boys	Girls	Boys
7 u	1 u	11x2 = 22 u	1x2 = 2 u

Total number of contestants in Team A
= 7 u + 1 u
= 8 u

Total number of contestants in Team B
= 3 x 8 u
= 24 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 24 and 12 is 24.

Number of more girls in Team B than Team A
= 22 u - 7 u
= 15 u

15 u = 150

1 u = 150 ÷ 15 = 10

Total number of contestants
= 7 u + 1 u + 22 u + 2 u
= 32 u
= 32 x 10
= 320

Answer(s): 320