What does this rebus mean?

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The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

If an electric train is travelling south, then which way is the smoke going?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

What does Alexander the Great and Winnie the Pooh have in common?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

If a wheel has 54 spokes, how many spaces are there between the spokes?

Solve the puzzle by telling what does below picture means.

There are nine dots in the picture that has been attached with this question. Can you join all the dots by drawing four straight lines without picking up your pen?

You can see three almost identical images below. Can you spot the odd one out from them?