A train increases its normal speed by 12.5% and reaches its destination 20 minutes earlier. What is the actual time taken by the train in the journey?

The correct answer is (b).

Let $x$ be the original time taken by the train. If the train increases its speed by 12.5%, then the new time taken is $\frac{112.5}{100}x = \frac{27}{20}x$. Since the new time is 20 minutes earlier, we have $\frac{27}{20}x = x – 20$. Solving for $x$, we get $x = \boxed{180}$ minutes.

Option (a) is incorrect because it is the time taken by the train if it does not increase its speed. Option (c) is incorrect because it is the time