A store decides to shut down and sell all of its inventory.  They have 2000 different items which would normally retail for $50.  They are offering an 80% discount and manage to sell 90% of the items.  They owed $15000 to their creditors.  How much money do they have left after the sale?
They sold 2000*.9=<<2000*.9=1800>>1800 items
They offered a 50*.8=$<<50*.8=40>>40 discount
That means that each item sold for 50-40=$<<50-40=10>>10
So they made 1800*10=$<<1800*10=18000>>18,000
So they had 18,000-15,000=$<<18000-15000=3000>>3,000 leftover
#### 3000