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 1.82 m in the same test. The total average of the whole class was 1.67 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
15 |
1 u |
1 u + 15 |
Value |
1.55 |
1.82 |
1.67 |
Total Value |
23.25 |
1.82 u |
1.67 u + 25.05 |
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 1.82
= 1.82 u
Total length that the children jumped
= 1.67(1 u + 15)
= 1.67 u + 25.05
23.25 + 1.82 u = 1.67 u + 25.05
1.82 u - 1.67 u = 25.05 - 23.25
0.15 u = 1.8
1 u = 1.8 ÷ 0.15 = 12
Number of boys
= 1 u
= 12
Answer(s): 12