In a class, 9 girls jumped an average of 1.32 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.46 m in the same test. The total average of the whole class was 1.37 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
9 |
1 u |
1 u + 9 |
Value |
1.32 |
1.46 |
1.37 |
Total Value |
11.88 |
1.46 u |
1.37 u + 12.33 |
Total number of boys = 1 u
Total number of children = 1 u + 9
Total length that the girls jumped
= 9 x 1.32
= 11.88 m
Total length that the boys jumped
= 1 u x 1.46
= 1.46 u
Total length that the children jumped
= 1.37(1 u + 9)
= 1.37 u + 12.33
11.88 + 1.46 u = 1.37 u + 12.33
1.46 u - 1.37 u = 12.33 - 11.88
0.09 u = 0.45
1 u = 0.45 ÷ 0.09 = 5
Number of boys
= 1 u
= 5
Answer(s): 5