The average number of boys in 3A, 3B and 3C is 14. This is 3 more than the average number of girls in the 3 rooms.
311 of the total number of girls are in 3C.
12 of the number of girls in 3B is the same as
111 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 29 pupils in 3A?
| Girls in 3A |
Girls in 3B |
Girls in 3C |
Total girls |
| 8 |
3 |
11 |
| |
2 |
|
11 |
| 6 u |
2 u |
3 u |
11 u |
12 of girls in 3B =
111 of all girls
Girls in 3B : All girls = 2 : 11
Average number of girls
= 14 - 3
= 11
Total number of girls
= 3 x 11
= 33
11 u = 33
1 u = 33 ÷ 11 = 3
Number of girls in Room 3A
= 6 u
= 6 x 3
= 18
Number of boys in Room 3A
= 29 - 18
= 11
Total number of boys
= 3 x 14
= 42
Boys in 3ATotal boys =
1142 Answer(s):
1142 
