In a class, 8 girls jumped an average of 1.21 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.48 m in the same test. The total average of the whole class was 1.3 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
8 |
1 u |
1 u + 8 |
Value |
1.21 |
1.48 |
1.3 |
Total Value |
9.68 |
1.48 u |
1.3 u + 10.4 |
Total number of boys = 1 u
Total number of children = 1 u + 8
Total length that the girls jumped
= 8 x 1.21
= 9.68 m
Total length that the boys jumped
= 1 u x 1.48
= 1.48 u
Total length that the children jumped
= 1.3(1 u + 8)
= 1.3 u + 10.4
9.68 + 1.48 u = 1.3 u + 10.4
1.48 u - 1.3 u = 10.4 - 9.68
0.18 u = 0.72
1 u = 0.72 ÷ 0.18 = 4
Number of boys
= 1 u
= 4
Answer(s): 4