I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Replace the question mark with the number below given a simple math problem.

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

Can you find out the missing number in the grid?

Why are all black people so quick ?

Why do we preferably have round manhole covers and not square ones?