The sale price after both markdowns will be $336
<em><u>Explanation</u></em>
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 
and the selling price after first 6 months will be: 
After another 6 months of not selling , it is further marked down by 20%. So, the marked down amount now 
Thus, the final selling price after all markdowns 