I am white when I am dirty, and black when I am clean. What am I?

Two friends were stuck in a cottage. They had nothing to do and thus they started playing cards. Suddenly the power went off and Friend 1 inverted the position of 15 cards in the normal deck of 52 cards and shuffled it. Now he asked Friend 2 to divide the cards into two piles (need not be equal) with equal number of cards facing up. The room was quite dark and Friend 2 could not see the cards. He thinks for a while and then divides the cards in two piles.

On checking, the count of cards facing up is same in both the piles. How could Friend 2 have done it ?

Why are all black people so quick ?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

What is the fastest way to double your money?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

Can you identify the famous TV character from the rebus below?

What will you call your mother's brother's brother-in-law?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

Replace the question mark with the correct number.