In a class, 8 girls jumped an average of 1.55 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.71 m in the same test. The total average of the whole class was 1.63 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
8 |
1 u |
1 u + 8 |
Value |
1.55 |
1.71 |
1.63 |
Total Value |
12.4 |
1.71 u |
1.63 u + 13.04 |
Total number of boys = 1 u
Total number of children = 1 u + 8
Total length that the girls jumped
= 8 x 1.55
= 12.4 m
Total length that the boys jumped
= 1 u x 1.71
= 1.71 u
Total length that the children jumped
= 1.63(1 u + 8)
= 1.63 u + 13.04
12.4 + 1.71 u = 1.63 u + 13.04
1.71 u - 1.63 u = 13.04 - 12.4
0.08 u = 0.64
1 u = 0.64 ÷ 0.08 = 8
Number of boys
= 1 u
= 8
Answer(s): 8