Barbara bought some presents for her relatives at an average price of $11.80. If Barbara decided to buy a pen which cost $16 for her father and a bag which cost $38 for her mother, the average price of the presents would become $15.60. How many presents did Barbara buy for her relatives?
| |
Relatives |
Relatives and parents |
| Number |
1 u |
1 u + 2 |
| Value |
11.80 |
15.60 |
| Total Value |
11.80 u |
15.60 u + 31.20 |
Number of presents that Barbara bought for her relatives = 1 u
Amount that Barbara spent on the presents for her relatives
= 1 u x 11.80
= 11.80 u
Amount that $(Lizy) spent if she bought for her parents
= 16 + 38
= $54
Total number of items bought if she bought for her parents and her relatives
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her relatives
= 15.60(1 u + 2)
= 15.60 u + 31.20
11.8 u + 54 = 15.60 u + 31.20
15.60 u - 11.8 u = 54 - 31.20
3.8 u = 22.80
1 u = 22.80 ÷ 3.8 = 6
Number of presents that she bought for her relatives
= 1 u
= 6
Answer(s): 6
