Solution given:
p(x)=0
-0.2x2 + 10x – 25=0
-0.2(x²-50x+125)=0
x²-2.25.x+25²=25²-125
(x-25)²=500
x-25=
x-25=±10√5
taking positive
x=22.3606+25
x=47.3606
taking negative
x= -22.3606+25
x=2.639
so
maximum profit Anthony will receive :47.3606*1000= 47360600(approach)
now
47360 .6 or 2639 parts he would need to sell to receive the maximum profit