Ivory bought some presents for her cousins at an average price of $13.50. If Ivory decided to buy a pen which cost $13 for her father and a bag which cost $37 for her mother, the average price of the presents would become $15.80. How many presents did Ivory buy for her cousins?
| |
Cousins |
Cousins and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.50 |
15.80 |
| Total Value |
13.50 u |
15.80 u + 31.60 |
Number of presents that Ivory bought for her cousins = 1 u
Amount that Ivory 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 + 37
= $50
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
= 15.80(1 u + 2)
= 15.80 u + 31.60
13.5 u + 50 = 15.80 u + 31.60
15.80 u - 13.5 u = 50 - 31.60
2.3 u = 18.40
1 u = 18.40 ÷ 2.3 = 8
Number of presents that she bought for her cousins
= 1 u
= 8
Answer(s): 8
