Question

The least number of complete years in which a sum of money put out at 20% compound interest will be more than doubled is:
A.3
B.4
C.5
D.6

Answer 1

C one is your answer

Answer 2

Answer:

4

Step-by-step explanation:

P [1 + (r/100)]^n  >  2P

⇒     P [1 + (20/100)]^n  >  2P

        [1 + (2/10) ]^n  > 2

        [12 / 10]^n  > 2

        [6/5]^n  > 2

         {6/5 * 6/5 * 6/5 * 6/5}  >  2

         ∴ n = 4

hence option B is the answer