21 pupils in a class sold an average of 17 cartoon figurines for charity. There were 7 more girls than boys in the class. The average number of cartoon figurines sold by the girls was 14. Find the average number of cartoon figurines sold by the boys.
| |
Boys |
Girls |
Total |
| Number |
1 u |
1 u + 7 |
21 |
| Value |
? |
14 |
17 |
| Total value |
161 |
196 |
357 |
Total number of cartoon figurines sold
= 21 x 17
= 357
Number of boys = 1 u
Number of girls = 1 u + 7
1 u + 1 u + 7 = 21
2 u + 7 = 21
2 u = 21 - 7
2 u = 14
1 u = 14 ÷ 2 = 7
Number of girls in class
= 1 u + 7
= 7 + 7
= 14
Number of cartoon figurines sold by girls
= 14 x 14
= 196
Number of cartoon figurines sold by boys
= 357 - 196
= 161
Average number of cartoon figurines sold by boys
= 161 ÷ 7
= 23
Answer(s): 23
