Erika bought some souvenirs for her colleagues at an average price of $10.50. If Erika decided to buy a pen which cost $19 for her father and a bag which cost $49 for her mother, the average price of the souvenirs would become $15.20. How many souvenirs did Erika buy for her colleagues?
| |
Colleagues |
Colleagues and parents |
| Number |
1 u |
1 u + 2 |
| Value |
10.50 |
15.20 |
| Total Value |
10.50 u |
15.20 u + 30.40 |
Number of souvenirs that Erika bought for her colleagues = 1 u
Amount that Erika spent on the souvenirs for her colleagues
= 1 u x 10.50
= 10.50 u
Amount that $(Lizy) spent if she bought for her parents
= 19 + 49
= $68
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
= 15.20(1 u + 2)
= 15.20 u + 30.40
10.5 u + 68 = 15.20 u + 30.40
15.20 u - 10.5 u = 68 - 30.40
4.7 u = 37.60
1 u = 37.60 ÷ 4.7 = 8
Number of souvenirs that she bought for her colleagues
= 1 u
= 8
Answer(s): 8
