Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

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

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Can you find the 09 errors in the picture below?

Client Dempsey living in one of the East Coast states of the U.S. was talking to Landon Donovan, who was living in the West Coast state of the U.S.

Dempsey: What time is it?
Donovan: Wow, It is the same time here.

How is this possible?

what does this below rebus represent identXQQQQQME

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

What do you call a fish without an eye?