If a drink needs to buy X boxes, then a drink needs to buy (500-x) boxes, and the total cost of buying two drinks does not exceed 20,000 yuan, then you will get it.

55x+35(500-x)≤20000, the solution is: x≤ 125.

If the profit from selling these two drinks in the mall is Y, then

y=(63-55)x+(40-35)(500-x)

=3x+2500

∵3>0,

∴y increases with the increase of X. To maximize Y, X should take the maximum value, and the maximum value of X is 125.

Therefore, when x= 125, the maximum value of y is 3× 125+2055=2875 yuan.