The average number of boys in 5A, 5B and 5C is 16. This is 2 more than the average number of girls in the 3 rooms.
37 of the total number of girls are in 5C.
52 of the number of girls in 5B is the same as
57 of the total number of girls in the 3 rooms. What fraction of the total number of boys in the 3 rooms is in 5A if there are 25 pupils in 5A?
| Girls in 5A |
Girls in 5B |
Girls in 5C |
Total girls |
| 4 |
3 |
7 |
| |
2 |
|
7 |
| 2 u |
2 u |
3 u |
7 u |
52 of girls in 5B =
57 of all girls
Girls in 5B : All girls = 2 : 7
Average number of girls
= 16 - 2
= 14
Total number of girls
= 3 x 14
= 42
7 u = 42
1 u = 42 ÷ 7 = 6
Number of girls in Room 5A
= 2 u
= 2 x 6
= 12
Number of boys in Room 5A
= 25 - 12
= 13
Total number of boys
= 3 x 16
= 48
Boys in 5ATotal boys =
1348 Answer(s):
1348 
