Question

a certain sum of money doubles itself at simple interest in 8 years. In how many years will it be three times at the same rate

Answer 1

please see the attachment.

Answer 2

Answer:

16 years

Step-by-step explanation:

Let the principle be x.

Then amount will be 2x.

Interest= Amount - Principal = 2x-x=x

Time = 8 yrs  

R=?  

$SI =\frac{P\times R \times T}{100}$

$x =\frac{x \times R \times 8}{100}$

 $\frac{100 \times x}{x \times 8} =R$

 $\frac{100}{8} =R$

Now Amount will be 3 times i.e. 3x

So, Interest=Amount - Principal = 3x-x=2x

$2x=\frac{x \times \frac{100}{8} \times T}{100}$

$\frac{2x \times 100}{x \times \frac{100}{8}}=T$

 $16=T$

So, It will take 16 years to be three times at the same rate