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 3 : 1. The ratio of the number of girls to boys in Team B is 5 : 1. There are 3 times as many pupils in Team B as in Team A. There are 77 more girls in Team B than Team A. What is the total number of boys?
Team A |
Team B |
4 u |
6x2 = 12 u |
Girls |
Boys |
Girls |
Boys |
3 u |
1 u |
5x2 = 10 u |
1x2 = 2 u
|
Total number of pupils in Team A
= 3 u + 1 u
= 4 u
Total number of pupils in Team B
= 3 x 4 u
= 12 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 12 and 6 is 12.
Number of more girls in Team B than Team A
= 10 u - 3 u
= 7 u
7 u = 77
1 u = 77 ÷ 7 = 11
Total number of boys
= 1 u + 2 u
= 3 u
= 3 x 11
= 33
Answer(s): 33