Emma bought some presents for her colleagues at an average price of $13.20. If Emma decided to buy a pen which cost $17 for her father and a bag which cost $43 for her mother, the average price of the presents would become $15.30. How many presents did Emma buy for her colleagues?
| |
Colleagues |
Colleagues and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.20 |
15.30 |
| Total Value |
13.20 u |
15.30 u + 30.60 |
Number of presents that Emma bought for her colleagues = 1 u
Amount that Emma spent on the presents for her colleagues
= 1 u x 13.20
= 13.20 u
Amount that $(Lizy) spent if she bought for her parents
= 17 + 43
= $60
Total number of items bought if she bought for her parents and her colleagues
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her colleagues
= 15.30(1 u + 2)
= 15.30 u + 30.60
13.2 u + 60 = 15.30 u + 30.60
15.30 u - 13.2 u = 60 - 30.60
2.1 u = 29.40
1 u = 29.40 ÷ 2.1 = 14
Number of presents that she bought for her colleagues
= 1 u
= 14
Answer(s): 14
