In a class, 9 girls jumped an average of 1.42 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.66 m in the same test. The total average of the whole class was 1.54 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
9 |
1 u |
1 u + 9 |
Value |
1.42 |
1.66 |
1.54 |
Total Value |
12.78 |
1.66 u |
1.54 u + 13.86 |
Total number of boys = 1 u
Total number of children = 1 u + 9
Total length that the girls jumped
= 9 x 1.42
= 12.78 m
Total length that the boys jumped
= 1 u x 1.66
= 1.66 u
Total length that the children jumped
= 1.54(1 u + 9)
= 1.54 u + 13.86
12.78 + 1.66 u = 1.54 u + 13.86
1.66 u - 1.54 u = 13.86 - 12.78
0.12 u = 1.08
1 u = 1.08 ÷ 0.12 = 9
Number of boys
= 1 u
= 9
Answer(s): 9