The average number of boys in 2A, 2B and 2C is 18. This is 4 more than the average number of girls in the 3 rooms.
27 of the total number of girls are in 2C.
12 of the number of girls in 2B is the same as
17 of the total number of girls in the 3 rooms. What fraction of the total number of boys in the 3 rooms is in 2A if there are 31 students in 2A?
Girls in 2A |
Girls in 2B |
Girls in 2C |
Total girls |
5 |
2 |
7 |
|
2 |
|
7 |
3 u |
2 u |
2 u |
7 u |
12 of girls in 2B =
17 of all girls
Girls in 2B : All girls = 2 : 7
Average number of girls
= 18 - 4
= 14
Total number of girls
= 3 x 14
= 42
7 u = 42
1 u = 42 ÷ 7 = 6
Number of girls in Room 2A
= 3 u
= 3 x 6
= 18
Number of boys in Room 2A
= 31 - 18
= 13
Total number of boys
= 3 x 18
= 54
Boys in 2ATotal boys =
1354 Answer(s):
1354