Brain Teasers

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You
don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go
through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth ,the other
always lies and you don't know which is which.
What is the question you ask?
Ans - ask Any Robot a question "According to him (another Robot) which door is safe?"
======================================
A frog is at the bottom of a 30 meter well. Each day he summons enough energy for one 3 meter leap up the
well. Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters
backwards. How many days does it take him to escape from the well?
Note: Assume after the first leap that his hind legs are exactly three meters up the well. His hind legs must
clear the well for him to escape.
Ans - 28 (27th day + 1 day for clearing 3 meter)
=========================================
Cathy has six pairs of black socks and six pairs of white socks in her drawer.
In complete darkness, and without looking, how many socks must she take from the drawer in order to be
sure to get a pair that match?
Ans - Socks do not come in in left and right, so any black will pair with any other black and any white will pair
with any other white. If you have three socks and they are either colored black or white, then you will have at
least two socks of the same color, giving you one matching pair.
==========================================
Mary's mum has four children.The first child is called April.The second May.The third June.What is the name of the fourth child?
Ans - Mary
========================================
You are mixing cement and the recipe calls for five gallons of water. You have a garden hose giving you all
the water you need. The problem is that you only have a four gallon bucket and a seven gallon bucket and
nether has graduation marks. Find a method to measure five gallons.
Ans - Pour the four gallon bucket filled with water into the empty seven gallon bucket. Fill the four gallon
bucket up again and poor as much as you can into the seven gallon bucket until the seven gallon bucket is
fill. Now there is one gallon left in the four gallon bucket. Empty the seven gallon bucket and transfer the one
gallon of water into the seven gallon bucket. Fill the four gallon bucket one more time, then pour the four
gallons into the seven gallon bucket making which already has one gallon in it, making a total of five gallons
=========================================
You have two strings whose only known property is that when you light one end of either string it takes
exactly one hour to burn. The rate at which the strings will burn is completely random and each string is
different.
How do you measure 45 minutes?
Ans - Light both the ends of the first string and one end of the second string. 30 minutes will have passed
when the first string is fully burned, which means 30 minutes have burned off the second string. Light the end
of the second string and when it is fully burned, 45 minutes will have passed.
=========================================
A corporate businessman has two cubes on his office desk. Every day he arranges both cubes so that the
front faces show the current day of the month.
What numbers are on the faces of the cubes to allow this?
Note: You can't represent the day "7" with a single cube with a side that says 7 on it. You have to use both
cubes all the time. So the 7th day would be "07".
Ans - Cube One has the following numbers: 0, 1, 2, 3, 4, 5
Cube two has the following numbers: 0, 1, 2, 6, 7, 8
The 6 doubles as a 9 when turned the other way around.
There is no day 00, but you still need the 0 on both cubes in order to make all the numbers between 01 and
09.
===========================================