Profit =(4X+8)(2400-2000-50x)

=4*50*(x+2)(8-x)

=200*( 16+6x-x^2)

=200*[25-(x^2-6x+9)]

=200*[25-(x-3)^2]

When x=3, the profit is the largest, that is, the price is reduced by 3×50= 150 yuan.

Maximum profit = 200× [25-(3-3) 2] = 5000 yuan.