Question

a sum of money becomes 27 times of itself in 3 years at compound interest . the rate of interest per annum is

Answer 1

Answer:

let the sum of money be X

X(1+r/100)^3=27x

(1+r/100)^3=27x/X

(1+r/100)^3=27

(1+r/100)^3=3^3

1+r/100=3

r/100=3-1

r/100=2

r=200

Hence, rate of interest=200%

Answer 2

The rate of interest per annum is 200 %.

Explanation:

Given:

   The amount is the 27 times the principal.

   Total time period for the interest to be paid = 3 years.

     

    So, let p be the principal amount.

We, know the compound interest.

     

                             ⇒ A = P x $(1-r)^{3}$

Here, A is the total amount.

   So,

                            ⇒ 27 = $(1-r)^{3}$

                              ⇒ r = 2

So, rate of interest is 200%.