In a class, 14 girls jumped an average of 1.53 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.61 m in the same test. The total average of the whole class was 1.57 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
14 |
1 u |
1 u + 14 |
Value |
1.53 |
1.61 |
1.57 |
Total Value |
21.42 |
1.61 u |
1.57 u + 21.98 |
Total number of boys = 1 u
Total number of children = 1 u + 14
Total length that the girls jumped
= 14 x 1.53
= 21.42 m
Total length that the boys jumped
= 1 u x 1.61
= 1.61 u
Total length that the children jumped
= 1.57(1 u + 14)
= 1.57 u + 21.98
21.42 + 1.61 u = 1.57 u + 21.98
1.61 u - 1.57 u = 21.98 - 21.42
0.04 u = 0.56
1 u = 0.56 ÷ 0.04 = 14
Number of boys
= 1 u
= 14
Answer(s): 14