In a class, 8 girls jumped an average of 1.28 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.52 m in the same test. The total average of the whole class was 1.4 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
8 |
1 u |
1 u + 8 |
Value |
1.28 |
1.52 |
1.4 |
Total Value |
10.24 |
1.52 u |
1.4 u + 11.2 |
Total number of boys = 1 u
Total number of children = 1 u + 8
Total length that the girls jumped
= 8 x 1.28
= 10.24 m
Total length that the boys jumped
= 1 u x 1.52
= 1.52 u
Total length that the children jumped
= 1.4(1 u + 8)
= 1.4 u + 11.2
10.24 + 1.52 u = 1.4 u + 11.2
1.52 u - 1.4 u = 11.2 - 10.24
0.12 u = 0.96
1 u = 0.96 ÷ 0.12 = 8
Number of boys
= 1 u
= 8
Answer(s): 8