In a class, 15 girls jumped an average of 1.52 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.8 m in the same test. The total average of the whole class was 1.6 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
15 |
1 u |
1 u + 15 |
Value |
1.52 |
1.8 |
1.6 |
Total Value |
22.8 |
1.8 u |
1.6 u + 24 |
Total number of boys = 1 u
Total number of children = 1 u + 15
Total length that the girls jumped
= 15 x 1.52
= 22.8 m
Total length that the boys jumped
= 1 u x 1.8
= 1.8 u
Total length that the children jumped
= 1.6(1 u + 15)
= 1.6 u + 24
22.8 + 1.8 u = 1.6 u + 24
1.8 u - 1.6 u = 24 - 22.8
0.2 u = 1.2
1 u = 1.2 ÷ 0.2 = 6
Number of boys
= 1 u
= 6
Answer(s): 6