In a class, 14 girls jumped an average of 1.39 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.55 m in the same test. The total average of the whole class was 1.47 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
14 |
1 u |
1 u + 14 |
Value |
1.39 |
1.55 |
1.47 |
Total Value |
19.46 |
1.55 u |
1.47 u + 20.58 |
Total number of boys = 1 u
Total number of children = 1 u + 14
Total length that the girls jumped
= 14 x 1.39
= 19.46 m
Total length that the boys jumped
= 1 u x 1.55
= 1.55 u
Total length that the children jumped
= 1.47(1 u + 14)
= 1.47 u + 20.58
19.46 + 1.55 u = 1.47 u + 20.58
1.55 u - 1.47 u = 20.58 - 19.46
0.08 u = 1.12
1 u = 1.12 ÷ 0.08 = 14
Number of boys
= 1 u
= 14
Answer(s): 14