The average number of girls in 5A, 5B and 5C is 15. This is 4 more than the average number of boys in the 3 rooms.
211 of the total number of boys are in 5C.
32 of the number of boys in 5B is the same as
311 of the total number of boys in the 3 rooms. What fraction of the total number of girls in the 3 rooms is in 5A if there are 34 children in 5A?
| Boys in 5A |
Boys in 5B |
Boys in 5C |
Total boys |
| 9 |
2 |
11 |
| |
2 |
|
11 |
| 7 u |
2 u |
2 u |
11 u |
32 of boys in 5B =
311 of all boys
Boys in 5B : All boys = 2 : 11
Average number of boys
= 15 - 4
= 11
Total number of boys
= 3 x 11
= 33
11 u = 33
1 u = 33 ÷ 11 = 3
Number of boys in Room 5A
= 7 u
= 7 x 3
= 21
Number of girls in Room 5A
= 34 - 21
= 13
Total number of girls
= 3 x 15
= 45
Girls in 5ATotal girls =
1345 Answer(s):
1345 
