An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

What brings you down but never up?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

In the given picture, in how many ways can you read the word "Tiger"?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Replace the question mark with the correct number below.