In a class, 6 girls jumped an average of 1.56 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.75 m in the same test. The total average of the whole class was 1.69 m. How many boys were there?
| |
Girls |
Boys |
Children |
| Number |
6 |
1 u |
1 u + 6 |
| Value |
1.56 |
1.75 |
1.69 |
| Total Value |
9.36 |
1.75 u |
1.69 u + 10.14 |
Total number of boys = 1 u
Total number of children = 1 u + 6
Total length that the girls jumped
= 6 x 1.56
= 9.36 m
Total length that the boys jumped
= 1 u x 1.75
= 1.75 u
Total length that the children jumped
= 1.69(1 u + 6)
= 1.69 u + 10.14
9.36 + 1.75 u = 1.69 u + 10.14
1.75 u - 1.69 u = 10.14 - 9.36
0.06 u = 0.78
1 u = 0.78 ÷ 0.06 = 13
Number of boys
= 1 u
= 13
Answer(s): 13
