In a class, 10 girls jumped an average of 1.37 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 1.44 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.37 |
1.49 |
1.44 |
Total Value |
13.7 |
1.49 u |
1.44 u + 14.4 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.37
= 13.7 m
Total length that the boys jumped
= 1 u x 1.49
= 1.49 u
Total length that the children jumped
= 1.44(1 u + 10)
= 1.44 u + 14.4
13.7 + 1.49 u = 1.44 u + 14.4
1.49 u - 1.44 u = 14.4 - 13.7
0.05 u = 0.7
1 u = 0.7 ÷ 0.05 = 14
Number of boys
= 1 u
= 14
Answer(s): 14