What has many keys but can’t open a single lock?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

How many words can a pen with half refill write?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

Rob is taller than Edwin, and Jurgen is shorter than Rob.
Of only one of the following statements, we now certainly know it is correct:

A.Edwin is taller than Jurgen
B.Jurgen is taller than Edwin
C.It cannot be determined if Jurgen or Edwin is the tallest.

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

A father's child, a mother's child, yet no one's son.

Who am I?

How can you make number one disappear by adding something to it?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?