In a class, 7 girls jumped an average of 1.43 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.69 m in the same test. The total average of the whole class was 1.56 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
7 |
1 u |
1 u + 7 |
Value |
1.43 |
1.69 |
1.56 |
Total Value |
10.01 |
1.69 u |
1.56 u + 10.92 |
Total number of boys = 1 u
Total number of children = 1 u + 7
Total length that the girls jumped
= 7 x 1.43
= 10.01 m
Total length that the boys jumped
= 1 u x 1.69
= 1.69 u
Total length that the children jumped
= 1.56(1 u + 7)
= 1.56 u + 10.92
10.01 + 1.69 u = 1.56 u + 10.92
1.69 u - 1.56 u = 10.92 - 10.01
0.13 u = 0.91
1 u = 0.91 ÷ 0.13 = 7
Number of boys
= 1 u
= 7
Answer(s): 7