In a class, 7 girls jumped an average of 1.33 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.51 m in the same test. The total average of the whole class was 1.45 m. How many boys were there?
| |
Girls |
Boys |
Children |
| Number |
7 |
1 u |
1 u + 7 |
| Value |
1.33 |
1.51 |
1.45 |
| Total Value |
9.31 |
1.51 u |
1.45 u + 10.15 |
Total number of boys = 1 u
Total number of children = 1 u + 7
Total length that the girls jumped
= 7 x 1.33
= 9.31 m
Total length that the boys jumped
= 1 u x 1.51
= 1.51 u
Total length that the children jumped
= 1.45(1 u + 7)
= 1.45 u + 10.15
9.31 + 1.51 u = 1.45 u + 10.15
1.51 u - 1.45 u = 10.15 - 9.31
0.06 u = 0.84
1 u = 0.84 ÷ 0.06 = 14
Number of boys
= 1 u
= 14
Answer(s): 14
