well, he got 1080, that's for 12 TVs each one with a warranty, let's take out the warranty commission, so each one is 20 bucks so for 12 that'd be 12*20 = 240, so 1080 - 240 = 840 is left.
so the fixed income for all 12 TVs is 840 bucks, how much per each one? well, 840 ÷ 12 = 70.