Question

determine the rate of interest per annum for a sum that becomes 729/625 of itself in one year compounded half yearly​

Answer 1

Let the principal be P

Given, time = 2 years and Rate of interest = ?

then Amount (A)

= 729 / 625 P

Now,

A = P [ 1 + r / 100 ] n

729 / 625 P = P [1 + r / 100 ]²

729 / 625 = [1 + r / 100 ]²

[27 / 25]² = [1 + r / 100]²

27 / 25 = 1+ r / 100

27 / 25 - 1 = r / 100

r / 100 = 2 / 25

r = 8

so, for 2 years

R x 2

i. e., 8 x 2 = 16 %