In a bank, principal increases continuously at the rate of 5% per year. In how many years Rs 1000 double itself?

Explanation

$$ \frac{d p}{d t}=\left(\frac{5}{100}\right) \times P $$
$$or \frac{d \mathrm{p}}{\mathrm{dt}}=\frac{\mathrm{P}}{20} \ldots \ldots \ldots(1)$$
separating the variables in equation (1), we get
$$ \frac{\mathrm{dp}}{\mathrm{P}}=\frac{\mathrm{dt}}{20} \ldots \ldots \ldots \ldots(2) $$
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