Fred bought some files at $5 each. He later sold them to his customers at $9 each. For customers who bought two files were given another file for free. The customers bought either one or two files. Fred gave away 140 free files and collected a total of $1260 more than what he had paid for. How many customers bought just one file each?
|
Files sold |
Files given to customers who got 1 file each |
Files given to customers who got 3 files each |
Number |
1 u |
1 u - 420 |
420 |
Value |
$5 |
$9 |
$9 |
Total Value |
5 u |
9 u - $3780 |
$2520 |
Since 140 files were given free, there were 140 customers who bought two files each.
Number of files that each customer would get if they bought two files each and got 1 file free
= 2 + 1
= 3
Total number of files for customers who each bought two files
= 3 x 140
= 420
Number of files for customers who each bought 1 file = 1 u - 420
Total amount collected from customers who bought 1 file each
= 9 x (1 u - 420)
= 9 u - 3780
Total amount collected from customers who bought two files each
= 140 x 2 x 9
= $2520
Total amount collected from all the customers
= 9 u - 3780 + 2520
= 9 u - 1260
Fred collected a total of $1260 more than what he had paid for.
9 u - 1260 = 5 u + 1260
9 u - 5 u = 1260 + 1260
4 u = 2520
1 u = 2520 ÷ 4 = 630
Number of customers who bought just one file
= 1 u - 420
= 630 - 420
= 210
Answer(s): 210