In a class, 13 girls jumped an average of 1.54 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.76 m in the same test. The total average of the whole class was 1.65 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
13 |
1 u |
1 u + 13 |
Value |
1.54 |
1.76 |
1.65 |
Total Value |
20.02 |
1.76 u |
1.65 u + 21.45 |
Total number of boys = 1 u
Total number of children = 1 u + 13
Total length that the girls jumped
= 13 x 1.54
= 20.02 m
Total length that the boys jumped
= 1 u x 1.76
= 1.76 u
Total length that the children jumped
= 1.65(1 u + 13)
= 1.65 u + 21.45
20.02 + 1.76 u = 1.65 u + 21.45
1.76 u - 1.65 u = 21.45 - 20.02
0.11 u = 1.43
1 u = 1.43 ÷ 0.11 = 13
Number of boys
= 1 u
= 13
Answer(s): 13