In a class, 11 girls jumped an average of 1.39 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.43 m in the same test. The total average of the whole class was 1.41 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
11 |
1 u |
1 u + 11 |
Value |
1.39 |
1.43 |
1.41 |
Total Value |
15.29 |
1.43 u |
1.41 u + 15.51 |
Total number of boys = 1 u
Total number of children = 1 u + 11
Total length that the girls jumped
= 11 x 1.39
= 15.29 m
Total length that the boys jumped
= 1 u x 1.43
= 1.43 u
Total length that the children jumped
= 1.41(1 u + 11)
= 1.41 u + 15.51
15.29 + 1.43 u = 1.41 u + 15.51
1.43 u - 1.41 u = 15.51 - 15.29
0.02 u = 0.22
1 u = 0.22 ÷ 0.02 = 11
Number of boys
= 1 u
= 11
Answer(s): 11