27 children in a class sold an average of 18 coins for charity. There were 9 more girls than boys in the class. The average number of coins sold by the girls was 16. Find the average number of coins sold by the boys.
|
Boys |
Girls |
Total |
Number |
1 u |
1 u + 9 |
27 |
Value |
? |
16 |
18 |
Total value |
198 |
288 |
486 |
Total number of coins sold
= 27 x 18
= 486
Number of boys = 1 u
Number of girls = 1 u + 9
1 u + 1 u + 9 = 27
2 u + 9 = 27
2 u = 27 - 9
2 u = 18
1 u = 18 ÷ 2 = 9
Number of girls in class
= 1 u + 9
= 9 + 9
= 18
Number of coins sold by girls
= 18 x 16
= 288
Number of coins sold by boys
= 486 - 288
= 198
Average number of coins sold by boys
= 198 ÷ 9
= 22
Answer(s): 22