In a class, 15 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 1.59 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
15 |
1 u |
1 u + 15 |
Value |
1.55 |
1.71 |
1.59 |
Total Value |
23.25 |
1.71 u |
1.59 u + 23.85 |
Total number of boys = 1 u
Total number of children = 1 u + 15
Total length that the girls jumped
= 15 x 1.55
= 23.25 m
Total length that the boys jumped
= 1 u x 1.71
= 1.71 u
Total length that the children jumped
= 1.59(1 u + 15)
= 1.59 u + 23.85
23.25 + 1.71 u = 1.59 u + 23.85
1.71 u - 1.59 u = 23.85 - 23.25
0.12 u = 0.6
1 u = 0.6 ÷ 0.12 = 5
Number of boys
= 1 u
= 5
Answer(s): 5