PSLE
The pupils at a camp are divided in Group A and Group B. The ratio of the number of boys to girls in Group A is 4 : 3. The ratio of the number of boys to girls in Group B is 9 : 5. There are 4 times as many pupils in Group B as in Group A. There are 182 more boys in Group B than Group A. What is the total number of girls?

Group A		Group B
7 u		14x2 = 28 u
Boys	Girls	Boys	Girls
4 u	3 u	9x2 = 18 u	5x2 = 10 u

Total number of pupils in Group A
= 4 u + 3 u
= 7 u

Total number of pupils in Group B
= 4 x 7 u
= 28 u

The total number of pupils in Group B is repeated.
Use LCM to make the total number of pupils in Group B the same.
LCM of 28 and 14 is 28.

Number of more boys in Group B than Group A
= 18 u - 4 u
= 14 u

14 u = 182

1 u = 182 ÷ 14 = 13

Total number of girls
= 3 u + 10 u
= 13 u
= 13 x 13
= 169

Answer(s): 169