Diana bought some presents for her siblings at an average price of $12.70. If Diana decided to buy a pen which cost $16 for her father and a bag which cost $34 for her mother, the average price of the presents would become $16.80. How many presents did Diana buy for her siblings?
| |
Siblings |
Siblings and parents |
| Number |
1 u |
1 u + 2 |
| Value |
12.70 |
16.80 |
| Total Value |
12.70 u |
16.80 u + 33.60 |
Number of presents that Diana bought for her siblings = 1 u
Amount that Diana spent on the presents for her siblings
= 1 u x 12.70
= 12.70 u
Amount that $(Lizy) spent if she bought for her parents
= 16 + 34
= $50
Total number of items bought if she bought for her parents and her siblings
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her siblings
= 16.80(1 u + 2)
= 16.80 u + 33.60
12.7 u + 50 = 16.80 u + 33.60
16.80 u - 12.7 u = 50 - 33.60
4.1 u = 16.40
1 u = 16.40 ÷ 4.1 = 4
Number of presents that she bought for her siblings
= 1 u
= 4
Answer(s): 4
