In a class, 12 girls jumped an average of 1.34 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.42 m in the same test. The total average of the whole class was 1.36 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
12 |
1 u |
1 u + 12 |
Value |
1.34 |
1.42 |
1.36 |
Total Value |
16.08 |
1.42 u |
1.36 u + 16.32 |
Total number of boys = 1 u
Total number of children = 1 u + 12
Total length that the girls jumped
= 12 x 1.34
= 16.08 m
Total length that the boys jumped
= 1 u x 1.42
= 1.42 u
Total length that the children jumped
= 1.36(1 u + 12)
= 1.36 u + 16.32
16.08 + 1.42 u = 1.36 u + 16.32
1.42 u - 1.36 u = 16.32 - 16.08
0.06 u = 0.24
1 u = 0.24 ÷ 0.06 = 4
Number of boys
= 1 u
= 4
Answer(s): 4