ArithmeticIf sum of money becomes triples in 20 years, the rate of interest per annum is

If sum of money becomes triples in 20 years, the rate of interest per annum is

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

$\begin{array}{l} 2 P = \frac{P \times 20 \times R}{100} \\ R = 10 % \end{array}$