In a class, 10 girls jumped an average of 1.22 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.44 m in the same test. The total average of the whole class was 1.34 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.22 |
1.44 |
1.34 |
Total Value |
12.2 |
1.44 u |
1.34 u + 13.4 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.22
= 12.2 m
Total length that the boys jumped
= 1 u x 1.44
= 1.44 u
Total length that the children jumped
= 1.34(1 u + 10)
= 1.34 u + 13.4
12.2 + 1.44 u = 1.34 u + 13.4
1.44 u - 1.34 u = 13.4 - 12.2
0.1 u = 1.2
1 u = 1.2 ÷ 0.1 = 12
Number of boys
= 1 u
= 12
Answer(s): 12