Gillian bought some gifts for her friends at an average price of $13.50. If Gillian decided to buy a pen which cost $14 for her father and a bag which cost $40 for her mother, the average price of the gifts would become $18.90. How many gifts did Gillian buy for her friends?
| |
Friends |
Friends and parents |
| Number |
1 u |
1 u + 2 |
| Value |
13.50 |
18.90 |
| Total Value |
13.50 u |
18.90 u + 37.80 |
Number of gifts that Gillian bought for her friends = 1 u
Amount that Gillian spent on the gifts for her friends
= 1 u x 13.50
= 13.50 u
Amount that $(Lizy) spent if she bought for her parents
= 14 + 40
= $54
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
= 18.90(1 u + 2)
= 18.90 u + 37.80
13.5 u + 54 = 18.90 u + 37.80
18.90 u - 13.5 u = 54 - 37.80
5.4 u = 16.20
1 u = 16.20 ÷ 5.4 = 3
Number of gifts that she bought for her friends
= 1 u
= 3
Answer(s): 3
