In a class, 12 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 1.27 m in the same test. The total average of the whole class was 1.24 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
12 |
1 u |
1 u + 12 |
Value |
1.21 |
1.27 |
1.24 |
Total Value |
14.52 |
1.27 u |
1.24 u + 14.88 |
Total number of boys = 1 u
Total number of children = 1 u + 12
Total length that the girls jumped
= 12 x 1.21
= 14.52 m
Total length that the boys jumped
= 1 u x 1.27
= 1.27 u
Total length that the children jumped
= 1.24(1 u + 12)
= 1.24 u + 14.88
14.52 + 1.27 u = 1.24 u + 14.88
1.27 u - 1.24 u = 14.88 - 14.52
0.03 u = 0.36
1 u = 0.36 ÷ 0.03 = 12
Number of boys
= 1 u
= 12
Answer(s): 12