So with what we know we can set up two equations to solve for the CDs and the players.
$12(300) = total earnings for cds
= $3600 total cds sold
$35(100) = total earnings for cd players
=$35000
add both of the totals of the CDs and the CD players to get the total earnings
$3600+$3500 = $7100 gained in total from both products sold