In a class, 10 girls jumped an average of 1.21 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.43 m in the same test. The total average of the whole class was 1.32 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
10 |
1 u |
1 u + 10 |
Value |
1.21 |
1.43 |
1.32 |
Total Value |
12.1 |
1.43 u |
1.32 u + 13.2 |
Total number of boys = 1 u
Total number of children = 1 u + 10
Total length that the girls jumped
= 10 x 1.21
= 12.1 m
Total length that the boys jumped
= 1 u x 1.43
= 1.43 u
Total length that the children jumped
= 1.32(1 u + 10)
= 1.32 u + 13.2
12.1 + 1.43 u = 1.32 u + 13.2
1.43 u - 1.32 u = 13.2 - 12.1
0.11 u = 1.1
1 u = 1.1 ÷ 0.11 = 10
Number of boys
= 1 u
= 10
Answer(s): 10