David has $1,800 at the beginning of his trip, after spending money, he still has exactly $800 less than he spent on the trip. How much money does John still have? Select:
A) $200 B) $500 C) $600 D) $800 E) $1,200
Suppose total money spent = x   Not spend (Money he still has)= x-800   x+x-800 = 1800   x= 1300   Money not spend= 1300-800= 
<gadget id="calculator">1300-800</gadget>
<output>500</output>
500   Answer : $500
<result>B</result>
David has $1,800 at the beginning of his trip, after spending money, he still has exactly $800 less than he spent on the trip. How much money does John still have?