In how many years will a sum of money double itself at 18.75% per annum simple interest?

$$\eqalign{ & {\text{Let sum = Rs}}{\text{. }}x{\text{}} \cr & {\text{Then,}} \cr & {\text{S}}{\text{.I}}{\text{. = Rs}}{\text{. }}x{\text{}} \cr & \therefore \text{Time} = \left( {\frac{{100 \times {\text{S}}{\text{.I}}{\text{.}}}}{{{\text{P}} \times {\text{R}}}}} \right) \cr & = \left( {\frac{{100 \times x}}{{x \times 18.75}}} \right){\text{years}} \cr & = \frac{{26}}{3}{\text{years}} \cr & = 5\frac{1}{3}{\text{years}} \cr & = {\text{5 years 4 months}}{\text{}} \cr} $$