Kathy bought some presents for her cousins at an average price of $13.50. If Kathy decided to buy a pen which cost $13 for her father and a bag which cost $46 for her mother, the average price of the presents would become $15.10. How many presents did Kathy buy for her cousins?
| |
Cousins |
Cousins and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.50 |
15.10 |
| Total Value |
13.50 u |
15.10 u + 30.20 |
Number of presents that Kathy bought for her cousins = 1 u
Amount that Kathy spent on the presents for her cousins
= 1 u x 13.50
= 13.50 u
Amount that $(Lizy) spent if she bought for her parents
= 13 + 46
= $59
Total number of items bought if she bought for her parents and her cousins
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her cousins
= 15.10(1 u + 2)
= 15.10 u + 30.20
13.5 u + 59 = 15.10 u + 30.20
15.10 u - 13.5 u = 59 - 30.20
1.6 u = 28.80
1 u = 28.80 ÷ 1.6 = 18
Number of presents that she bought for her cousins
= 1 u
= 18
Answer(s): 18
