A and B invests Rs.3000 and Rs.6000 respectively in a business. If A doubles his capital after 6 months. In what ratio should A and B divide that year's profit?
Choose the correct choice from the following.
A) 9 : 6
B) 3 : 8
C) 3 : 1
D) 9 : 9
E) 3 : 4

Rationale: "( 3 * 6 + 6 * 6 ) : ( 6 * 12 ) 18 : 24 = > 3 : 4 . answer : e"
Answer: E