Give stream of consciousness and then the final answer. On 3,000 invested at a simple interest rate 6 p.c.p.a, 900 is obtained as interest in certain years. In order to earn 1,600 as interest on 4,000 in the same number of years, what should be the rate of simple interest?
Options:
(A) 7 p.c.p.a.
(B) 8 p.c.p.a.
(C) 9 p.c.p.a.
(D) Data inadequate
(E) None of these

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Time = 900×100/3000×6 = 5 years
Rate = 1600×100/5×4000 = 8%
The final answer: (B).