The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

Chef Andrea has to light the kitchen stoves to open her restaurant for the day. There are three stoves in the kitchen: A glass stove, a brick stove, and a wood stove. She only has one match. Which does she light up first?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What can you see in the middle of March and April that you can never see in any other month?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

The horse jumps over the king.
Strangely there is absolutely no scratch on him.

Can anyone explain, how is this possible?