The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

Replace the question mark with the correct number in the below-given picture?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
=====
* * *

Solve this riddle by finding the odd one out from the rest.

Find the next number in the sequence

5 12 24 36 ?

If 1+9+8=1, what is 2+8+9?

Count the number of lines in the image below ?