What number when divided in half becomes zero?

I make two people out of one. What am I?

Can it be possible to build a house that has all its four walls facing towards the South?

There are hundred red gems and hundred blue gems. The blue gems are priceless while the red gems equal wastage. You have two sacks one labeled Heads and the other Tails. You have to distribute the gems as you want in the two sacks. Then a coin will be flipped and you will be asked to pick up a gem randomly from the corresponding sacks.

How will you distribute the gems between the sacks so that the odds of picking a Blue gem are maximum?

A man dies of old age on his 25 birthday. How is this possible?

John and his wife were living in a rural place. On a particular day, John's wife fell ill and he called the local doctor. When the doctor picked up, he said, "Doctor, my wife is ill. She might have appendicitis."

"This can't be possible! I took out her appendix two years ago myself," the doctor explained.

When diagnosed, John's wife was found to have appendicitis. How can this be possible?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

81 x 9 = 801. What must you do to make the this equation true?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?