What four weights can be used to balance from 1 to 30 pounds?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Why do people go to bed?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

You’ll find me on Mercury, Earth, Mars, Jupiter, Saturn, and Uranus. But never Neptune, or Venus. What am I?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?