What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

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?

What can go up a chimney down, but can’t go down a chimney up?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

Solve the alphametic puzzle by replacing the alphabet with the number.

S T O R M +
S O L E S
=========
T O W E L
=========

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?