Kimberly bought some presents for her friends at an average price of $13.90. If Kimberly decided to buy a pen which cost $18 for her father and a bag which cost $40 for her mother, the average price of the presents would become $14.10. How many presents did Kimberly buy for her friends?
| |
Friends |
Friends and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.90 |
14.10 |
| Total Value |
13.90 u |
14.10 u + 28.20 |
Number of presents that Kimberly bought for her friends = 1 u
Amount that Kimberly spent on the presents for her friends
= 1 u x 13.90
= 13.90 u
Amount that $(Lizy) spent if she bought for her parents
= 18 + 40
= $58
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
= 14.10(1 u + 2)
= 14.10 u + 28.20
13.9 u + 58 = 14.10 u + 28.20
14.10 u - 13.9 u = 58 - 28.20
0.2 u = 29.80
1 u = 29.80 ÷ 0.2 = 149
Number of presents that she bought for her friends
= 1 u
= 149
Answer(s): 149
