In a class, 7 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 1.46 m in the same test. The total average of the whole class was 1.37 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
7 |
1 u |
1 u + 7 |
Value |
1.28 |
1.46 |
1.37 |
Total Value |
8.96 |
1.46 u |
1.37 u + 9.59 |
Total number of boys = 1 u
Total number of children = 1 u + 7
Total length that the girls jumped
= 7 x 1.28
= 8.96 m
Total length that the boys jumped
= 1 u x 1.46
= 1.46 u
Total length that the children jumped
= 1.37(1 u + 7)
= 1.37 u + 9.59
8.96 + 1.46 u = 1.37 u + 9.59
1.46 u - 1.37 u = 9.59 - 8.96
0.09 u = 0.63
1 u = 0.63 ÷ 0.09 = 7
Number of boys
= 1 u
= 7
Answer(s): 7