A person bought 10 bottles for 1 dollar. How many for a dollar must he sell to gain 100%?	Choose the correct option:
A) 1
B) 2
C) 3
D) 4
E) 5
C.P. of 10 bottles = $1   S.P. of 10 bottles = 200% of $1 =2   for $2 bottles sold = 10   for $1 bottles sold = 10/2= 
<gadget id="calculator">10/2</gadget>
<output>5</output>
5   Answer is 5
<result>E</result>
A person bought 10 bottles for 1 dollar. How many for a dollar must he sell to gain 100%?