Trick Teaser Riddles

#11 - Logic Interview Question

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.

How many such operations are necessary to correctly label the boxes?

#12 - Monty Hall Problem Puzzle

The host of a game show, offers the guest a choice of three doors. Behind one is a 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?

#13 - No Uninvited Guest Puzzle

Queen Elizabeth organized a royal party.

To Avoid uninvited guest royal family set a password.
Wayne (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Wayne thought is enough and he walked to the entry point. The security person said 'eight' , Wayne replied smilingly 'four'.
He was immediately thrown out of the party.

why ?

#14 - Most Famous Maths Puzzle

I can prove why 1 = 2

* Lets say y = x
* Multiply through by x xy = x2
* Subtract y2 from each side xy - y2 = x2 - y2
* Factor each side y(x-y) = (x+y)(x-y)
* Divide both sides by (x-y) y = x+y
* Divide both sides by y y/y = x/y + y/y
* And so... 1 = x/y + 1
* Since x=y, x/y = 1 1 = 1 + 1
* And so... 1 = 2

How is this possible ?

#15 - Classic Logical Interview Puzzle

I have two rectangular wires.
Both of them have property that when i light the fire from one end , it will take 60 minutes to get completely burn.
However they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could i measure 45 minutes ?

#16 - Logic Problem Puzzle

A donkey travels the exact same distance daily.
strangely 2 of his legs travels 40 kilometers and the remaining two travels 41 kilometers.
Obviously 2 donkey legs cannot be a 1km ahead of the other 2.

The donkey is perfectly normal. So how come this be true ?

#17 - Short Jokes Riddles

1. How can we put a elephant in the refrigerator ?
2. How can we put a Giraffe in a refrigerator ?
3. The king of the jungle invites all the animals to a party everyone comes except for one animal, which animal ?
4. You come to a crocodile infested lake, you can't go around it, you can't co under it and you can't go over it, how do you get across ?

#18 - What Is Time Riddle

I noticed that on my big wall clock, there is a time when the minute and hour clock are exactly between one and two.
Also, I notice both hands lie on top of each other.

What is the time I am talking about?

#19 - Infogain Interview Aptitude Question

On a magical land of Narnia , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since its a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

#20 - Logical Thinking Riddle

I have 100 coins in my wallet.

What is the minimum number of coin(s), i would be required in order to make sure each coin touched exactly three other coins.