In a class, 8 girls jumped an average of 1.45 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.53 m in the same test. The total average of the whole class was 1.49 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
8 |
1 u |
1 u + 8 |
Value |
1.45 |
1.53 |
1.49 |
Total Value |
11.6 |
1.53 u |
1.49 u + 11.92 |
Total number of boys = 1 u
Total number of children = 1 u + 8
Total length that the girls jumped
= 8 x 1.45
= 11.6 m
Total length that the boys jumped
= 1 u x 1.53
= 1.53 u
Total length that the children jumped
= 1.49(1 u + 8)
= 1.49 u + 11.92
11.6 + 1.53 u = 1.49 u + 11.92
1.53 u - 1.49 u = 11.92 - 11.6
0.04 u = 0.32
1 u = 0.32 ÷ 0.04 = 8
Number of boys
= 1 u
= 8
Answer(s): 8