In a class, 11 girls jumped an average of 1.26 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 1.34 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
11 |
1 u |
1 u + 11 |
Value |
1.26 |
1.42 |
1.34 |
Total Value |
13.86 |
1.42 u |
1.34 u + 14.74 |
Total number of boys = 1 u
Total number of children = 1 u + 11
Total length that the girls jumped
= 11 x 1.26
= 13.86 m
Total length that the boys jumped
= 1 u x 1.42
= 1.42 u
Total length that the children jumped
= 1.34(1 u + 11)
= 1.34 u + 14.74
13.86 + 1.42 u = 1.34 u + 14.74
1.42 u - 1.34 u = 14.74 - 13.86
0.08 u = 0.88
1 u = 0.88 ÷ 0.08 = 11
Number of boys
= 1 u
= 11
Answer(s): 11