In a class, 10 girls jumped an average of 1.45 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.59 m in the same test. The total average of the whole class was 1.52 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.45 |
1.59 |
1.52 |
Total Value |
14.5 |
1.59 u |
1.52 u + 15.2 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.45
= 14.5 m
Total length that the boys jumped
= 1 u x 1.59
= 1.59 u
Total length that the children jumped
= 1.52(1 u + 10)
= 1.52 u + 15.2
14.5 + 1.59 u = 1.52 u + 15.2
1.59 u - 1.52 u = 15.2 - 14.5
0.07 u = 0.7
1 u = 0.7 ÷ 0.07 = 10
Number of boys
= 1 u
= 10
Answer(s): 10