In order to build a "Scholarly Campus", a school plans to use no more than 1900 science and technology books and 1620 personal literature books to set up a total of 30 small and medium-sized book corners. It is known that to set up a medium-sized book corner, 80 science and technology books and 50 humanities books are needed; to set up a small book corner, 30 science and technology books and 60 humanities books are needed. (1) what are the construction plans in line with the theme How many? Please help the school design; (2) if the cost of setting up a medium-sized book corner is 860 yuan, and that of setting up a small book corner is 570 yuan, which one is the lowest in (1)? How much is the minimum charge?

In order to build a "Scholarly Campus", a school plans to use no more than 1900 science and technology books and 1620 personal literature books to set up a total of 30 small and medium-sized book corners. It is known that to set up a medium-sized book corner, 80 science and technology books and 50 humanities books are needed; to set up a small book corner, 30 science and technology books and 60 humanities books are needed. (1) what are the construction plans in line with the theme How many? Please help the school design; (2) if the cost of setting up a medium-sized book corner is 860 yuan, and that of setting up a small book corner is 570 yuan, which one is the lowest in (1)? How much is the minimum charge?

(1) Let x medium-sized book corners be set up, then (30-x) small-sized book corners be set up. According to the meaning of the title, we get 80x + 30 (30 − x) ≤ 190050x + 60 (30 − x) ≤ 1620. By solving this inequality, we get 18 ≤ x ≤ 20. Because x can only take integers, the values of 〈 X are 18, 19, 20. When x = 18, 30-x = 12; when x = 19