24 students in a class sold an average of 16 erasers for charity. There were 6 more girls than boys in the class. The average number of erasers sold by the girls was 13. Find the average number of erasers sold by the boys.
| |
Boys |
Girls |
Total |
| Number |
1 u |
1 u + 6 |
24 |
| Value |
? |
13 |
16 |
| Total value |
189 |
195 |
384 |
Total number of erasers sold
= 24 x 16
= 384
Number of boys = 1 u
Number of girls = 1 u + 6
1 u + 1 u + 6 = 24
2 u + 6 = 24
2 u = 24 - 6
2 u = 18
1 u = 18 ÷ 2 = 9
Number of girls in class
= 1 u + 6
= 9 + 6
= 15
Number of erasers sold by girls
= 15 x 13
= 195
Number of erasers sold by boys
= 384 - 195
= 189
Average number of erasers sold by boys
= 189 ÷ 9
= 21
Answer(s): 21
