In a class, 12 girls jumped an average of 1.24 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.49 m in the same test. The total average of the whole class was 1.39 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
12 |
1 u |
1 u + 12 |
Value |
1.24 |
1.49 |
1.39 |
Total Value |
14.88 |
1.49 u |
1.39 u + 16.68 |
Total number of boys = 1 u
Total number of children = 1 u + 12
Total length that the girls jumped
= 12 x 1.24
= 14.88 m
Total length that the boys jumped
= 1 u x 1.49
= 1.49 u
Total length that the children jumped
= 1.39(1 u + 12)
= 1.39 u + 16.68
14.88 + 1.49 u = 1.39 u + 16.68
1.49 u - 1.39 u = 16.68 - 14.88
0.1 u = 1.8
1 u = 1.8 ÷ 0.1 = 18
Number of boys
= 1 u
= 18
Answer(s): 18