In a class, 12 girls jumped an average of 1.39 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 1.43 m. How many boys were there?
| |
Girls |
Boys |
Children |
| Number |
12 |
1 u |
1 u + 12 |
| Value |
1.39 |
1.46 |
1.43 |
| Total Value |
16.68 |
1.46 u |
1.43 u + 17.16 |
Total number of boys = 1 u
Total number of children = 1 u + 12
Total length that the girls jumped
= 12 x 1.39
= 16.68 m
Total length that the boys jumped
= 1 u x 1.46
= 1.46 u
Total length that the children jumped
= 1.43(1 u + 12)
= 1.43 u + 17.16
16.68 + 1.46 u = 1.43 u + 17.16
1.46 u - 1.43 u = 17.16 - 16.68
0.03 u = 0.48
1 u = 0.48 ÷ 0.03 = 16
Number of boys
= 1 u
= 16
Answer(s): 16
