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

Why Wine Glass Stem is so long?

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

What does below Rebus say?

XLR8

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

How many times do a clock's hands overlap in a day ?