Please help me out on this question, I'd really appreciate it. =w=
192000 = 28x + 40(6000 - x)
192000 = -12x + 240000
192000 - 240000 = -12x
-48000 = -12x
4000 = x
The number of sales for the $28 is 4000 and the number of sales for the $40 is 2000.