(3) According to the meaning of the question: m= 1, 2, 3, 4, 5, suppose that farmers * * * get a profit of W million yuan.

∴w=30﹙20﹣ 10﹚﹙60-2×20﹚+30﹙ 18- 10﹚﹙60-2× 18﹚+30﹙ 16- 10﹚﹙60-2× 16﹚+

30﹙ 14- 10﹚﹙60-2× 14﹚+30﹙ 12- 10﹚﹙60-2× 12﹚=6000+5760+5040+3840+2 160

= 22800 (yuan) =2.28 (ten thousand yuan)