24 students in a class sold an average of 16 postcards for charity. There were 8 more girls than boys in the class. The average number of postcards sold by the girls was 13. Find the average number of postcards sold by the boys.
| |
Boys |
Girls |
Total |
| Number |
1 u |
1 u + 8 |
24 |
| Value |
? |
13 |
16 |
| Total value |
176 |
208 |
384 |
Total number of postcards sold
= 24 x 16
= 384
Number of boys = 1 u
Number of girls = 1 u + 8
1 u + 1 u + 8 = 24
2 u + 8 = 24
2 u = 24 - 8
2 u = 16
1 u = 16 ÷ 2 = 8
Number of girls in class
= 1 u + 8
= 8 + 8
= 16
Number of postcards sold by girls
= 16 x 13
= 208
Number of postcards sold by boys
= 384 - 208
= 176
Average number of postcards sold by boys
= 176 ÷ 8
= 22
Answer(s): 22
