Peter bought some markers at $4 each. He later sold them to his customers at $6 each. For customers who bought four markers were given another marker for free. The customers bought either one or four markers. Peter gave away 120 free markers and collected a total of $620 more than what he had paid for. How many customers bought just one marker each?
|
Markers sold |
Markers given to customers who got 1 marker each |
Markers given to customers who got 5 markers each |
Number |
1 u |
1 u - 600 |
600 |
Value |
$4 |
$6 |
$6 |
Total Value |
4 u |
6 u - $3600 |
$2880 |
Since 120 markers were given free, there were 120 customers who bought four markers each.
Number of markers that each customer would get if they bought four markers each and got 1 marker free
= 4 + 1
= 5
Total number of markers for customers who each bought four markers
= 5 x 120
= 600
Number of markers for customers who each bought 1 marker = 1 u - 600
Total amount collected from customers who bought 1 marker each
= 6 x (1 u - 600)
= 6 u - 3600
Total amount collected from customers who bought four markers each
= 120 x 4 x 6
= $2880
Total amount collected from all the customers
= 6 u - 3600 + 2880
= 6 u - 720
Peter collected a total of $620 more than what he had paid for.
6 u - 720 = 4 u + 620
6 u - 4 u = 620 + 720
2 u = 1340
1 u = 1340 ÷ 2 = 670
Number of customers who bought just one marker
= 1 u - 600
= 670 - 600
= 70
Answer(s): 70