In how many years, a sum will triple itself at the rate of 10% simple interest per annum?

Correct option is A

​$$\textbf{Solution:} \\[5pt]\text{Let the Principal be } P. \\\text{If the amount triples, then Final Amount (A) = } 3P \\[5pt]\text{Simple Interest (SI) = A - P = } 3P - P = 2P \\[10pt]\text{We know the formula for Simple Interest:} \\SI = \frac{P \times R \times T}{100} \\[10pt]\text{Substitute the values:} \\2P = \frac{P \times 10 \times T}{100} \\[10pt]\text{Cancel } P \text{ from both sides:} \\2 = \frac{10 \times T}{100} \\[5pt]T = \frac{2 \times 100}{10} = 20 \text{ years} \\[10pt]\boxed{\text{The correct answer is: (a) 20 years}}$$​​