Question 308987
Let h=number of hats he bought.
1800/h cost of each hat
(1800/h)+20 sale price of each hat
h-5 number of hats he sells
2000 income from the sale of the hats
.
((1800/h)+20)(h-5)=2000
(1800+20h)(h-5)=2000h multiply each side by h to eliminate fraction.
20h^2+1700h-9000=2000h
h^2+85h-450=100
h^2-15h-450=0
(h-30)(h+15)=0
h=30 number of hats he bought.
.
Ed