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

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

Can you solve below mathematical equation?

2^1234 - 2^1233

Can you move from MANILA to UGANDA in the shortest time? You need to follow the below rules:
Rule 1: You can change up to 3 alphabets at a time.
Rule 2: New words must be of 6 alphabets.
Rule 3: The new word formed must be a country or capital.

Readers with the sharpest vision can find the eagle in the mountains in 6 seconds. Are you one of them? Test your observation skills now!

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

Find the last number in the series below:

voN luJ yaM raM ---

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Solve this logical number series puzzle by replacing the question mark with the correct number
9090 = 4
1234 = 0
6055 = 2
9081 = 4
8888 = ?