The average number of girls in 2A, 2B and 2C is 19. This is 5 more than the average number of boys in the 3 rooms.
27 of the total number of boys are in 2C.
32 of the number of boys in 2B is the same as
37 of the total number of boys in the 3 rooms. What fraction of the total number of girls in the 3 rooms is in 2A if there are 31 students in 2A?
| Boys in 2A |
Boys in 2B |
Boys in 2C |
Total boys |
| 5 |
2 |
7 |
| |
2 |
|
7 |
| 3 u |
2 u |
2 u |
7 u |
32 of boys in 2B =
37 of all boys
Boys in 2B : All boys = 2 : 7
Average number of boys
= 19 - 5
= 14
Total number of boys
= 3 x 14
= 42
7 u = 42
1 u = 42 ÷ 7 = 6
Number of boys in Room 2A
= 3 u
= 3 x 6
= 18
Number of girls in Room 2A
= 31 - 18
= 13
Total number of girls
= 3 x 19
= 57
Girls in 2ATotal girls =
1357 Answer(s):
1357 
