32 pupils in a class sold an average of 22 stamps for charity. There were 8 more girls than boys in the class. The average number of stamps sold by the girls was 13. Find the average number of stamps sold by the boys.
| |
Boys |
Girls |
Total |
| Number |
1 u |
1 u + 8 |
32 |
| Value |
? |
13 |
22 |
| Total value |
444 |
260 |
704 |
Total number of stamps sold
= 32 x 22
= 704
Number of boys = 1 u
Number of girls = 1 u + 8
1 u + 1 u + 8 = 32
2 u + 8 = 32
2 u = 32 - 8
2 u = 24
1 u = 24 ÷ 2 = 12
Number of girls in class
= 1 u + 8
= 12 + 8
= 20
Number of stamps sold by girls
= 20 x 13
= 260
Number of stamps sold by boys
= 704 - 260
= 444
Average number of stamps sold by boys
= 444 ÷ 12
= 37
Answer(s): 37
