Therefore, the countable inequality set 80x+30(30-x)≤ 1900 ①.
50x+60(30-x)≤ 1620 ②
Get 18≤x from ①.
② X≤20.
So the solution of this inequality group is 18≤x≤20.
Since x can only be an integer, the value of x is 18,19,20.
When x= 18, 30-x =12;
When x= 19, 30-x =11;
When x=20, 30-x = 10.
So there are three formation schemes:
Scheme 1: Set 18 middle corner and 12 small corner;
Scheme 2: Set 19 middle book corner and 1 1 small book corner;
Scheme 3: Set 20 medium-sized corners and 10 small corners.
① The cost of Scheme I is: 860× 18+570× 12.
= 15480+6840
=22320 (yuan);
② The cost of Scheme II is: 860×19+570×11.
= 16340+6270
=226 10 (yuan)
③ The cost of the third scheme is 860×20+570× 10.
= 17200+5700
=22900 (yuan)
22320 & lt226 10 & lt； 22900
Therefore, the first scheme has the lowest cost, and the lowest cost is 22,320 yuan.
I hope I can help you and wish you progress in your study.