Y = (2000-6X)*( 10+0.5X)

= -3X^2 +940X + 20000

(0 & lt= X & lt= 1 10)

(2)

According to the meaning of the question

-3x^2+940 x+20000-340 x-2000 * 10 = 22500

that is

-3X^2 + 600X - 22500 = 0

solve

X = 50 or X= 150 (because the domain of X is [0, 1 10], x= 150 is omitted).

That is, it needs to be preserved for 50 days before it can be released.

(3)

Maximum profit m =-3x2+940x+20000-340x-2000 *10.

=-3x 2+600 times

= -3(X- 100)^2 + 30000

When X = 100, there is a maximum value of 30000.

Therefore, after 100 days of storage, you can get the maximum profit of 30,000 yuan.

Thank you for adopting _