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!
