Pamela bought some presents for her friends at an average price of $12.90. If Pamela decided to buy a pen which cost $18 for her father and a bag which cost $35 for her mother, the average price of the presents would become $16.30. How many presents did Pamela buy for her friends?
| |
Friends |
Friends and parents |
| Number |
1 u |
1 u + 2 |
| Value |
12.90 |
16.30 |
| Total Value |
12.90 u |
16.30 u + 32.60 |
Number of presents that Pamela bought for her friends = 1 u
Amount that Pamela spent on the presents for her friends
= 1 u x 12.90
= 12.90 u
Amount that $(Lizy) spent if she bought for her parents
= 18 + 35
= $53
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
= 16.30(1 u + 2)
= 16.30 u + 32.60
12.9 u + 53 = 16.30 u + 32.60
16.30 u - 12.9 u = 53 - 32.60
3.4 u = 20.40
1 u = 20.40 ÷ 3.4 = 6
Number of presents that she bought for her friends
= 1 u
= 6
Answer(s): 6
