24 pupils in a class sold an average of 17 coins for charity. There were 8 more girls than boys in the class. The average number of coins sold by the girls was 13. Find the average number of coins sold by the boys.
| |
Boys |
Girls |
Total |
| Number |
1 u |
1 u + 8 |
24 |
| Value |
? |
13 |
17 |
| Total value |
200 |
208 |
408 |
Total number of coins sold
= 24 x 17
= 408
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 coins sold by girls
= 16 x 13
= 208
Number of coins sold by boys
= 408 - 208
= 200
Average number of coins sold by boys
= 200 ÷ 8
= 25
Answer(s): 25
