7, 7 dragons spend nine dollars to buy a handcart, turned sell 8 dollars; drinking and chatting with friends find themselves selling price below the market price, and my heart feel uncomfortable, to spend 10 dollars to buy the car back, re-sell at high prices to 11. Q: dragons how much money?
Generally, the selling price minus the cost price of 11 8 + 7 + 10, so dragons earned two dollars; but if the first time at a higher price to 11 dollars, he can earn three dollars, for a business to He said, I do not think he earned two is not lost one, but reduces the profits earned dollar.