②x≥22
22≤x≤30。 X is 22, 23, 24, 25, 26, 27, 28, 29, 30. There are 9 assembly schemes for A and B***. 2) The total overhead is y = 20x+ 18 (40-x) = 2x+70.
When k = 2 > 0, ∴y increases with the increase of x 。
When x=22, the total assembly cost is the least, and the minimum assembly cost is 2×22+720=764 yuan.
The assembly scheme with the lowest total assembly cost: 22 sets of A-type assembly and 8 sets of B-type assembly/KLOC-0.