Question

a sum of money becomes 4/3 of itself in 6 years at a certain rate of simple interest find the rate of interest.

Answer 1

Answer:

Rate of interest = 5.56%

Step-by-step explanation:

It is given that,

A sum of money becomes 4/3 of itself in 6 years at a certain rate of simple interest.

Let P be the principle amount, R be the rate of change and N be the number of years

Simple interest, I = (PNR)/100

To find the rate of interest

Here N = 6,

P + I = 4P/3

P + (PNR)/100 = 4P/3

P + (Px 6 xR)/100 = 4P/3

1 + 6R/100 = 4/3

300 + 18R = 400

18R = 100

R = 100/18 = 50/9 =  5.56%

Therefore rate of interest = 5.56%

Answer 2

Answer:

R=5.56%

Step-by-step explanation:

Let the sum be x

Amount = $\frac{4}{3}*x$

we know the formula for simple interest

Simple Interest = Amount-Sum

                           =$\frac{4}{3}*x-x$

                           =$\frac{x}{3}$

Let the rate be R%

Now

$S.I = \frac{P*R*T}{100}$

Where R is rate T is time and P is Sum

⇒$\frac{x}{3}=\frac{x*R*6}{100}$

⇒$\frac{x*100}{3*x*6}=R$

x cancels out

⇒$R=\frac{100}{3*6}$

R=$\frac{100}{18}$

R=5.56%