The sale price after both markdowns will be $336
Explanation
The selling price of an item is $600. After 6 months of not selling, it is marked down by 30%
So, the marked down amount after 6 months [tex]=\$ 600*0.30= \$180[/tex]
and the selling price after first 6 months will be: [tex]\$600-\$180=\$420[/tex]
After another 6 months of not selling , it is further marked down by 20%. So, the marked down amount now [tex]= \$420*0.20=\$84[/tex]
Thus, the final selling price after all markdowns [tex]=\$420-\$84=\$336[/tex]