In a class, 9 girls jumped an average of 1.53 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.76 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 |
9 |
1 u |
1 u + 9 |
Value |
1.53 |
1.76 |
1.67 |
Total Value |
13.77 |
1.76 u |
1.67 u + 15.03 |
Total number of boys = 1 u
Total number of children = 1 u + 9
Total length that the girls jumped
= 9 x 1.53
= 13.77 m
Total length that the boys jumped
= 1 u x 1.76
= 1.76 u
Total length that the children jumped
= 1.67(1 u + 9)
= 1.67 u + 15.03
13.77 + 1.76 u = 1.67 u + 15.03
1.76 u - 1.67 u = 15.03 - 13.77
0.09 u = 1.26
1 u = 1.26 ÷ 0.09 = 14
Number of boys
= 1 u
= 14
Answer(s): 14