Question

At simple interest, a sum of money doubles itself in ten years. Find the number of years it will take to triple itself.

• A. 20 years
• B. 24 years
• C. 25 years
• D. 30 years

Answer 1

The correct option is A 20 years

Let the principal be P.
As per the question, Amount = 2(Principal) = 2P
SI = Amount - Principal = 2P - P = P

By formula,
$R=\frac{SI\times 100}{P\times T}$
$R=\frac{P\times 100}{P\times 10}$
$=10$ %

So, the rate is 10% per annum. Now, the sum gets tripled.
A = 3(Principal) = 3P
SI = 3P - P = 2P
$T=\frac{SI\times 100}{P\times R}$
$T=\frac{2P\times 100}{P\times 10}$ = 20 years