In a class, 10 girls jumped an average of 1.46 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.61 m in the same test. The total average of the whole class was 1.51 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.46 |
1.61 |
1.51 |
Total Value |
14.6 |
1.61 u |
1.51 u + 15.1 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.46
= 14.6 m
Total length that the boys jumped
= 1 u x 1.61
= 1.61 u
Total length that the children jumped
= 1.51(1 u + 10)
= 1.51 u + 15.1
14.6 + 1.61 u = 1.51 u + 15.1
1.61 u - 1.51 u = 15.1 - 14.6
0.1 u = 0.5
1 u = 0.5 ÷ 0.1 = 5
Number of boys
= 1 u
= 5
Answer(s): 5