24 students in a class sold an average of 19 stamps for charity. There were 8 more boys than girls in the class. The average number of stamps sold by the boys was 18. Find the average number of stamps sold by the girls.
| |
Girls |
Boys |
Total |
| Number |
1 u |
1 u + 8 |
24 |
| Value |
? |
18 |
19 |
| Total value |
168 |
288 |
456 |
Total number of stamps sold
= 24 x 19
= 456
Number of girls = 1 u
Number of boys = 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 boys in class
= 1 u + 8
= 8 + 8
= 16
Number of stamps sold by boys
= 16 x 18
= 288
Number of stamps sold by girls
= 456 - 288
= 168
Average number of stamps sold by girls
= 168 ÷ 8
= 21
Answer(s): 21
