(1)每千克降价x元(60-x-40)*(100+x/2*20)=2240x^2-10x+24=0(x-4)(x-6)=0x=4,x=6 (2)设售价x元,利润y元y=(x-40)*[(60-x)/2*20+100] =-10x^2+1100x-2800 =-10(x-55)^2+27450y=-10(56-55)^2+27450=27440y=-10(54-55)^2+27450=27440当x=54至56元时,利润最大,为27440元