In a class, 10 girls jumped an average of 1.58 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.84 m in the same test. The total average of the whole class was 1.71 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.58 |
1.84 |
1.71 |
Total Value |
15.8 |
1.84 u |
1.71 u + 17.1 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.58
= 15.8 m
Total length that the boys jumped
= 1 u x 1.84
= 1.84 u
Total length that the children jumped
= 1.71(1 u + 10)
= 1.71 u + 17.1
15.8 + 1.84 u = 1.71 u + 17.1
1.84 u - 1.71 u = 17.1 - 15.8
0.13 u = 1.3
1 u = 1.3 ÷ 0.13 = 10
Number of boys
= 1 u
= 10
Answer(s): 10