In a class, 10 girls jumped an average of 1.49 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.73 m in the same test. The total average of the whole class was 1.58 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.49 |
1.73 |
1.58 |
Total Value |
14.9 |
1.73 u |
1.58 u + 15.8 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.49
= 14.9 m
Total length that the boys jumped
= 1 u x 1.73
= 1.73 u
Total length that the children jumped
= 1.58(1 u + 10)
= 1.58 u + 15.8
14.9 + 1.73 u = 1.58 u + 15.8
1.73 u - 1.58 u = 15.8 - 14.9
0.15 u = 0.9
1 u = 0.9 ÷ 0.15 = 6
Number of boys
= 1 u
= 6
Answer(s): 6