Natalie bought some presents for her colleagues at an average price of $12.70. If Natalie decided to buy a pen which cost $16 for her father and a bag which cost $39 for her mother, the average price of the presents would become $16.40. How many presents did Natalie buy for her colleagues?
| |
Colleagues |
Colleagues and parents |
| Number |
1 u |
1 u + 2 |
| Value |
12.70 |
16.40 |
| Total Value |
12.70 u |
16.40 u + 32.80 |
Number of presents that Natalie bought for her colleagues = 1 u
Amount that Natalie spent on the presents for her colleagues
= 1 u x 12.70
= 12.70 u
Amount that $(Lizy) spent if she bought for her parents
= 16 + 39
= $55
Total number of items bought if she bought for her parents and her colleagues
= 1 u + 1 + 1
= 1 u + 2
Total amount that she spent if she bought for her parents and her colleagues
= 16.40(1 u + 2)
= 16.40 u + 32.80
12.7 u + 55 = 16.40 u + 32.80
16.40 u - 12.7 u = 55 - 32.80
3.7 u = 22.20
1 u = 22.20 ÷ 3.7 = 6
Number of presents that she bought for her colleagues
= 1 u
= 6
Answer(s): 6
