Question

How much would you pay for 5,000 copies?

Answer 1

1) 1,000 copies = $25

2) There are 4,000 copies left and each 1,000 is $15

So
Additional 1,000 = $15
Additional 2,000 = $30
Additional 3,000 = $45
Additional 4,000 = $60

3)
1,000 copies = $25
Additional 4,000 copies = $60

$25 + $60 = $85

Hope this helped!