In a class, 7 girls jumped an average of 1.24 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.43 m in the same test. The total average of the whole class was 1.36 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
7 |
1 u |
1 u + 7 |
Value |
1.24 |
1.43 |
1.36 |
Total Value |
8.68 |
1.43 u |
1.36 u + 9.52 |
Total number of boys = 1 u
Total number of children = 1 u + 7
Total length that the girls jumped
= 7 x 1.24
= 8.68 m
Total length that the boys jumped
= 1 u x 1.43
= 1.43 u
Total length that the children jumped
= 1.36(1 u + 7)
= 1.36 u + 9.52
8.68 + 1.43 u = 1.36 u + 9.52
1.43 u - 1.36 u = 9.52 - 8.68
0.07 u = 0.84
1 u = 0.84 ÷ 0.07 = 12
Number of boys
= 1 u
= 12
Answer(s): 12