Question

a sum of rs 2000 amounts to rs 4000 in two years at compound interest. in how many years does the same amount becomes rs 8000

Answer 1

Answer:

Step-by-step explanation:

Amount A = P(1+I)^n where P is the principal, I is the rate of interest and n is the time in years.

So when A = RS.4000,P = RS. 2000

4000 = 2000(1+i)^2 => (1+i)^2 = 4000/2000

=> (1+I)^2 = 2 ……..(1)

Now when I get amount is RS.8000

8000 = 2000(1+I)^n

=> (1+I)^n = 8000/2000 = 4 = 2^2 = {(1+i)^2}^2

=> (1+i)^n =[(1+i)^4 => n = 4