PSLE The pupils at a school choir are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 7 : 1. The ratio of the number of boys to girls in Team B is 3 : 1. There are 2 times as many pupils in Team B as in Team A. There are 40 more boys in Team B than Team A. What is the total number of girls?
Team A |
Team B |
8 u |
4x4 = 16 u |
Boys |
Girls |
Boys |
Girls |
7 u |
1 u |
3x4 = 12 u |
1x4 = 4 u
|
Total number of pupils in Team A
= 7 u + 1 u
= 8 u
Total number of pupils in Team B
= 2 x 8 u
= 16 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 16 and 4 is 16.
Number of more boys in Team B than Team A
= 12 u - 7 u
= 5 u
5 u = 40
1 u = 40 ÷ 5 = 8
Total number of girls
= 1 u + 4 u
= 5 u
= 5 x 8
= 40
Answer(s): 40