A and B invests Rs.3000 and Rs.4000 respectively in a business. If A doubles his capital after 6 months. In what ratio should A and B divide that year's profit?
Select:  A) 9 : 6  B) 9 : 8  C) 9 : 0  D) 9 : 2  E) 9 : 1

Rationale: "( 3 * 6 + 6 * 6 ) : ( 4 * 12 ) 54 : 48 = > 9 : 8 answer : b"
Answer: B