Fred bought some staplers at $4 each. He later sold them to his customers at $9 each. For customers who bought two staplers were given another stapler for free. The customers bought either one or two staplers. Fred gave away 170 free staplers and collected a total of $1620 more than what he had paid for. How many customers bought just one stapler each?
|
Staplers sold |
Staplers given to customers who got 1 stapler each |
Staplers given to customers who got 3 staplers each |
Number |
1 u |
1 u - 510 |
510 |
Value |
$4 |
$9 |
$9 |
Total Value |
4 u |
9 u - $4590 |
$3060 |
Since 170 staplers were given free, there were 170 customers who bought two staplers each.
Number of staplers that each customer would get if they bought two staplers each and got 1 stapler free
= 2 + 1
= 3
Total number of staplers for customers who each bought two staplers
= 3 x 170
= 510
Number of staplers for customers who each bought 1 stapler = 1 u - 510
Total amount collected from customers who bought 1 stapler each
= 9 x (1 u - 510)
= 9 u - 4590
Total amount collected from customers who bought two staplers each
= 170 x 2 x 9
= $3060
Total amount collected from all the customers
= 9 u - 4590 + 3060
= 9 u - 1530
Fred collected a total of $1620 more than what he had paid for.
9 u - 1530 = 4 u + 1620
9 u - 4 u = 1620 + 1530
5 u = 3150
1 u = 3150 ÷ 5 = 630
Number of customers who bought just one stapler
= 1 u - 510
= 630 - 510
= 120
Answer(s): 120