Question

A certain sum become 3 times at the rate of 8% per annum. At what rate of interest the
same sum become 6 times in same duration​

Answer 1

Answer:

The new rate of interest in same duration is 20%.

Step-by-step explanation:

Let a certain sum be P.

And sum become 3 times =3P.

Rate =8% per annum.

S.I=3P-P

S.I=2P.

We know the formula of simple interest is:

$S.I=\dfrac{P\times R\times T}{100}$

$2P=\dfrac{P\times 8\times T}{100}$

$T=\dfrac{200}{8}\\T=25$year.

Now solving for the rate (R).

6 times of the same sum=6P.

S.I=6P-P

S.I=5P.

Formula using:

$S.I=\dfrac{P\times R\times T}{100}$

$5P=\dfrac{P\times R\times 25}{100}$

$P\times R\times 25=500P\\R\times 25=500\\R=\dfrac{500}{25}$

R=20%.