David has $2,400 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?  Choose the correct choice:
A) $200
B) $400
C) $600
D) $800
E) $1,200
Suppose total money spent = x   Not spend (Money he still has)= x-800   x+x-800 = 2400   x= 1600   Money not spend= 1600-800= 
<gadget id="calculator">1600-800</gadget>
<output>800</output>
800   Answer : $800
<result>D</result>
David has $2,400 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?