• Views : 50k+
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# #1 - Toughest Bulb Logic Interview Puzzle

Difficulty Popularity

There are 100 bulbs lined up in a room. All are turned on in the first pass. Then all the even numbered light bulbs are switched off. After that, every third bulb is switched on. Then all those bulbs that were switched off are turned back on and all those that were lit are turned off. Then the same process is being carried with the fourth bulb and the fifth bulb.

How many bulbs are glowing after 100 passes?

• Views : 50k+
• Sol Viewed : 20k+

# #2 - Crossing Bridge Interview Puzzle

Difficulty Popularity

The scenario comprises of a wobbly bridge and four people. It is the night time and the people have only one torch. Without torch one may risk his life in crossing the bridge. Also we have a condition; the bridge is not quite strong and can hold only two persons together at one. The four people take different time to cross the bridge - 1 min, 2 min, 7 min and 10 min.

Since the torch is a necessity and the bride can't hold more than two persons at a time, two persons must travel at a time out of which one must return with the torch so they don't risk their life crossing in the dark.

What is the shortest time that will be required for all of them to cross the bridge?

• Views : 50k+
• Sol Viewed : 20k+

# #3 - Monty Hall Interview Problem

Difficulty Popularity

Sarah and Michael are a loving couple. One night Sarah playfully places three identical boxes on a table in front of Michael. Out of the three boxes, one contains a pearl and other two are empty. Michael is then allowed to pick any one of them. Now between the two boxes that remain on the table, at least one is empty. Sarah removes one empty box from the table. Now Michael must choose from the box he picked or the box on the table.

What box should Michael choose?

• Views : 50k+
• Sol Viewed : 20k+

# #4 - Nine Hats Interview Puzzle

Difficulty Popularity

Nine brilliant most students were summoned by an inspecting professor. He gave them a situation and told them that he is having nine hats. The hats are either red colored or blue colored as told by the professor. He also tells them that he have at least one red colored hat and the number of blue hats are greater than the red hats.

He places one hat on each of their heads. The students are not allowed to talk with each other and no means of communication is feasible. He asks them how many hats are blue and how many are red. He gives them half an hour to deduce and moves out of the room. Nobody is able to answer when he returns back and thus he gives them another fifteen minutes. But when he returns, no one can answer again. Thus he gives them final five minutes. On returning back this time, everyone was available with an accurate answer.

How could the students have deduced the right answer? What is the right answer?

• Views : 50k+
• Sol Viewed : 20k+

# #5 - Fastest Horse Interview Puzzle

Difficulty Popularity

You are provided with twenty five different horses and you must find out who are the fastest horses. You can conduct a race of five horses only at one time. There is no point in the race where you can find out the actual speed of a horse in a race.

How many races will it take to help you determine the fastest three horses?

• Views : 50k+
• Sol Viewed : 20k+

# #6 - Two Eggs Interview Problem

Difficulty Popularity

Eggs have quite a unique property. They may be extremely fragile that they may break by mere a drop from your hand. However, they may not break even if they are dropped from the 100th floor. That is exactly what you have in this problem. You have two identical eggs and you have access to a 100 story building.

The question is how many drops you will make before you can find out the highest possible floor of the building from which the egg can be dropped without breaking. Remember you only have two eggs to break.

• Views : 50k+
• Sol Viewed : 20k+

# #7 - Truthcity or Liarcity Interview Puzzle

Difficulty Popularity

You are extremely excited to finally visit Truthcity, a city where everyone speaks truth forever their life. On way, you find a two diverging roads and there is no board to suggest which way leads to the Truthcity. However you do know that the other road leads to Liarcity, a city where every single person always speaks a lie. You meet a man passing by who allows you to ask one question as he will not answer more than one. The problem is that you don't know whether the man is from Truthcity or the Liarcity.

What is the question that you will pop up that tells you the way to Truthcity?

• Views : 50k+
• Sol Viewed : 20k+

# #8 - Ultimate Software Interview Mystery Puzzle

Difficulty Popularity

A lady is killed in her apartment. The possible suspect are all her ex - Peter, Jason, Fredd, Danny and Danke. On the crime scene, a calendar is found on which there are certain numbers that are being written with blood - 6, 4, 9, 10 and 11.

The police is not able to find out the killer and then Sherlock is called. Just a look at the numbers and he is able to deduce the killer. Can you?

• Views : 50k+
• Sol Viewed : 20k+

# #9 - Guess the Password Interview Puzzle

Difficulty Popularity

I was working in a highly secured company that needed to keep highest possible encryption. On a random day I logged into my system and it said password denied. Then it caught my attention that the passwords were changed randomly on any day for maximum security and that it could only be obtained from the boss in that case.

I went to the cabin of my boss and said, "Boss, my old password is out of dare."

He replied, "Yes I know about it. Though your new password is different, it has the same amount of letters as your previous one and also four of the letters are same."

• Views : 50k+
• Sol Viewed : 20k+

# #10 - Tricky Clock Interview Puzzle

Difficulty Popularity

If you see a reflection of an analogue clock which shows 2:30, what will be the original time?

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