In a class, 7 girls jumped an average of 1.35 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.41 m in the same test. The total average of the whole class was 1.39 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
7 |
1 u |
1 u + 7 |
Value |
1.35 |
1.41 |
1.39 |
Total Value |
9.45 |
1.41 u |
1.39 u + 9.73 |
Total number of boys = 1 u
Total number of children = 1 u + 7
Total length that the girls jumped
= 7 x 1.35
= 9.45 m
Total length that the boys jumped
= 1 u x 1.41
= 1.41 u
Total length that the children jumped
= 1.39(1 u + 7)
= 1.39 u + 9.73
9.45 + 1.41 u = 1.39 u + 9.73
1.41 u - 1.39 u = 9.73 - 9.45
0.02 u = 0.28
1 u = 0.28 ÷ 0.02 = 14
Number of boys
= 1 u
= 14
Answer(s): 14