Emily bought some presents for her friends at an average price of $13.10. If Emily decided to buy a pen which cost $15 for her father and a bag which cost $49 for her mother, the average price of the presents would become $17.30. How many presents did Emily buy for her friends?
| |
Friends |
Friends and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.10 |
17.30 |
| Total Value |
13.10 u |
17.30 u + 34.60 |
Number of presents that Emily bought for her friends = 1 u
Amount that Emily spent on the presents for her friends
= 1 u x 13.10
= 13.10 u
Amount that $(Lizy) spent if she bought for her parents
= 15 + 49
= $64
Total number of items bought if she bought for her parents and her friends
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her friends
= 17.30(1 u + 2)
= 17.30 u + 34.60
13.1 u + 64 = 17.30 u + 34.60
17.30 u - 13.1 u = 64 - 34.60
4.2 u = 29.40
1 u = 29.40 ÷ 4.2 = 7
Number of presents that she bought for her friends
= 1 u
= 7
Answer(s): 7
