35 children in a class sold an average of 22 marbles for charity. There were 5 more boys than girls in the class. The average number of marbles sold by the boys was 16. Find the average number of marbles sold by the girls.
| |
Girls |
Boys |
Total |
| Number |
1 u |
1 u + 5 |
35 |
| Value |
? |
16 |
22 |
| Total value |
450 |
320 |
770 |
Total number of marbles sold
= 35 x 22
= 770
Number of girls = 1 u
Number of boys = 1 u + 5
1 u + 1 u + 5 = 35
2 u + 5 = 35
2 u = 35 - 5
2 u = 30
1 u = 30 ÷ 2 = 15
Number of boys in class
= 1 u + 5
= 15 + 5
= 20
Number of marbles sold by boys
= 20 x 16
= 320
Number of marbles sold by girls
= 770 - 320
= 450
Average number of marbles sold by girls
= 450 ÷ 15
= 30
Answer(s): 30
