What is black when you buy it, red when you use it, and gray when you throw it away?

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

The more of this there is, the less you see. What is it?

Our product and our sum always give the same answer. Who are we?

In a certain bank, a man deposits a certain amount. According to the bank policies, the amount will be doubled up in a year but as the service charge, they will also deduct Rs. 65 by the end of every year.

If after the 6th year, the amount becomes 0, what do you think is the original amount he deposited in the bank?

Different lights make me strange by changing me into different sizes. What am I?

One day, all the courtiers from Akbar's court were gathered in the assembly hall when one of them told the Emperor that all his valuables had been stolen by a thief the previous night.
This shocked the Emperor to his core as the place where that courter stayed was the most secured in the kingdom. The Emperor thought that it is not at all possible for an outsider to enter into the courtier's house and steal the valuables. Only another courtier could commit this crime. He quickly called Birbal to identify the thief.
Birbal thought for a while and successfully solved the mystery by identifying the thief in just one statement.
What did Birbal say?

Can you write down eight eights so that they add up to one thousand?

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?