The average number of boys in 3A, 3B and 3C is 17. This is 3 more than the average number of girls in the 3 rooms.
17 of the total number of girls are in 3C.
32 of the number of girls in 3B is the same as
37 of the total number of girls in the 3 rooms. What fraction of the total number of boys in the 3 rooms is in 3A if there are 35 pupils in 3A?
| Girls in 3A |
Girls in 3B |
Girls in 3C |
Total girls |
| 6 |
1 |
7 |
| |
2 |
|
7 |
| 4 u |
2 u |
1 u |
7 u |
32 of girls in 3B =
37 of all girls
Girls in 3B : All girls = 2 : 7
Average number of girls
= 17 - 3
= 14
Total number of girls
= 3 x 14
= 42
7 u = 42
1 u = 42 ÷ 7 = 6
Number of girls in Room 3A
= 4 u
= 4 x 6
= 24
Number of boys in Room 3A
= 35 - 24
= 11
Total number of boys
= 3 x 17
= 51
Boys in 3ATotal boys =
1151 Answer(s):
1151 
