Opal bought some gifts for her cousins at an average price of $10.50. If Opal decided to buy a pen which cost $17 for her father and a bag which cost $40 for her mother, the average price of the gifts would become $17.70. How many gifts did Opal buy for her cousins?
| |
Cousins |
Cousins and parents |
| Number |
1 u |
1 u + 2 |
| Value |
10.50 |
17.70 |
| Total Value |
10.50 u |
17.70 u + 35.40 |
Number of gifts that Opal bought for her cousins = 1 u
Amount that Opal spent on the gifts for her cousins
= 1 u x 10.50
= 10.50 u
Amount that $(Lizy) spent if she bought for her parents
= 17 + 40
= $57
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
= 17.70(1 u + 2)
= 17.70 u + 35.40
10.5 u + 57 = 17.70 u + 35.40
17.70 u - 10.5 u = 57 - 35.40
7.2 u = 21.60
1 u = 21.60 ÷ 7.2 = 3
Number of gifts that she bought for her cousins
= 1 u
= 3
Answer(s): 3
