Question

A sum becomes 1.6 times of itself in five years at simple rate of interest. Find rate of interest per annum

Answer 1

Answer:

Step-by-step explanation:

Let the principal be P

Then, according to the question let the simple interest be S.I= P/2

Let rate of interest be r

Here time, t= 5 years

We know, S.I = P*r*t/100

=> P/2= P*r*5/100

=> R= 10

Hence the rate of interest would be 10%

Answer 2

Let sum = P,

rate of interest = r % per annum


we know , S.I = P × r × t/100

where t is time ,

also , A = P + S.I

it is given, that A = 1.6P and t = 5yrs

1.6P = P + P × r × 5/100

1.6P - 1P = Pr/20

0.6P = Pr/20

0.6 × 20 = r

r = 12 % per annum.