Critical Thinking Challenges | Tough Interview Puzzles

In our daily life, we come across many different problems. For some of these problems, at the beginning, we may think that they are impossible to solve. However, if we think critically and deeply, then we can find the solution to these problems easily. During our student life, we also come across many such practical problems where we need to do many different mathematical calculations or think very logically to find the solution to the given problems. Here are such critical thinking puzzles to challenge your mind.

How to Solve Critical Thinking Puzzles and Brain Teasers

These critical thinking brain teasers are a mix of both Mathematical Puzzles as well as Logical Puzzles. In these critical thinking brain teasers, you are given a puzzling statement that, at first glance, may look impossible to solve, but try to think out of the box; then you can find the solutions to these brain teasers very logically.

Let us see how many of these critical thinking puzzles you can solve without looking at the answers.

Coins Logical and Mathematical Brain Teaser

I) 11 coins are given to A, B, C, and D, with each having at least one coin. Now read the conversations among A, B, C, and D.
A: Hey B, do you have more coins than me?
B: I don't know: Hey C, do you have more coins than me?
C: I don't know:
D: I know exactly how many coins each one of us has.

Coins Logical and Mathematical Brain Teaser-Answer

I)As the total number of coins is 11. If B is given more than 4 coins, then his answer will be Yes, and if he is given 1 coin, then his answer will be NO. So B is having either 2, 3, or 4 coins.
Now come to the second question, which B asks C. 
So, B is having a minimum of 2 coins. C could have said NO if he is having 2 or fewer. So C is having either 3 or 4 coins.  

D can only say this statement if he is given 5 coins. Now D has 5 coins remaining; 6 coins can be divided into others as A=1, B=2, and C=3.

Mathematical Gold Coins Weight Puzzle

II) Gold coins in each bag containing 100 coins. One of the bags contains a gold coin that is .1gm more. Only one is weighed on the digital scale, and you have to find which bag contains the gold coin.

Mathematical Gold Coins Weight Puzzle - Answer

II) This can be solved with Mathematical Arithmetic Sequences. First, mark each of the bags from 1 to 100. Now take as many coins from the bag as the bag's marked number. e.g., take 1 coin from a bag marked 1, take 2 coins from a bag marked 2, 100 coins from a bag marked 100, and so on. Put all the coins together and weigh them together.

If there is no bag containing the coins that weigh .1gm then the sum of the weight of all these coins will be 1+2+3.................+100, which is 100(100+1)/2 = 50*101 = 5050 g. However, it will weigh higher than this, say by an amount X. So the bag number which contains gold coins with more weight is X/0.1 number. e.g., if X is 0.9, then 0.9/0.1 is the 9th bag which contains the gold coins which weigh more than other gold coins.

Switches Out of Box Thinking Brain Teaser

III) There are three switches downstairs. Each corresponds to one of the three light bulbs in the room. You can turn the switches on and off and leave them in any position.
How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?

Switches Out of Box Thinking Brain Teaser-Answer

III) You can solve it with the knowledge that a light bulb heats up with time.

Mark the Switches A, B, and C respectively. Turn on A for some time.

Now switch off A and Switch On B and quickly go to the room.

The ON bulb is linked to switch B. The bulb that is off and is hot is linked to Switch A, and the bulb which is off and is not hot is linked to Switch C.

Probability-based Pearl Brain Teaser

IV) There are 100 pearls kept in a bowl in front of you and an empty bowl. Among the 100 pearls, 50 are white, and 50 are black. You can divide them as you like into two bowls. Once you are done, you will pull a lever, which will turn the room pitch black. The bowls will move and shuffle around. In the dark, you have to pick up one pearl from any bowl. Once you do that, the room will flood with light again. If the pearl you have in your hand is white, you will be allowed to live, but if the pearl you picked is black, the room will be filled with poisonous gas, and you will die.
How will you divide the pearls to increase your chances of survival?

Probability-based Pearl Brain Teaser - Answer

IV) This is the probability-based puzzle. In this, you have to maximize the probability of your survival. To live, you should be getting the White Pearl.  So this is how you can divide the White and Black Pearls into two boxes for maximizing the probability of getting a White Pearl

Put one White Pearl in one box and the remaining 99 Pearls in another box.

Now the probability of your survival is maximized. Suppose you pick up the box that has only one White Pearl, which is 0.5 or 50% probability. So you survive in this case.

In another case, you pick up the box that has a mix of both White and Black Pearls. In this case, your probability of getting a white Pearl is 49/99, which is 0.495. So your total probability of survival is 0.500 + 0.495=0.995 i.e., 99.5%.

Mind-Boggling Logical Brain Teaser

V) 3 Logician walk-in bar. The bartender asks, "Do you ALL want a drink?"
1st Logician answers, "I don't know"
2nd Logician says, "I don't know"
3rd one says, "Yes"
What's going on here?

Mind-Boggling Logical Brain Teaser Solution

V) Answer key to this drink logical puzzle is in the question which Bartender asks "Do you ALL want a drink?" Here the key lies in the word "ALL".

1st logician wants the drink; otherwise his answer to this question will be "No". He is sure of himself wanting the drink but is not sure about the other two. So he answers "I don't know". Similarly, from the first Logician's answer, the 2nd Logician can deduce that the 1st one wants a drink, and the 2nd Logician also wants a drink, but he was not sure about the third one. So he answers "I don't know". Now the 3rd one wants the drink, and from the previous answers, he could deduce that the other two also wanted the drink. This is the reason he answered "Yes".

Great Logical Blue and Red Pill Brain Teaser

VI) John's father, Harry, is a great scientist. He invents two types of pills. One is the Red Pill, and another is the Blue Pill. Taking one Red Pill and one Blue Pill will make a person Superman for some time. However, if two Red pills or two Blue pills are taken together, then the person will die immediately. Harry gives two Red pills and two Blue pills to his son John.
After a few days, John is kidnapped and kept in a dark room where he cannot see the color of the pills. How will he make sure that he consumes one blue pill and one red pill to become Superman and then escape? Do remember that if he consumes two Blue or Two Red pills at the same time, he will die immediately.

Great Logical Blue and Red Pill Brain Teaser  - Answer

VI) John will take half of each pill to make it a total of 1 Blue pill and 1 Red pill.

Out-of-Box Thinking Mathematical Age Brain Teaser

VII) A census enumerator named Tony visits Bill's house. Bill is a very famous Math Professor. Tony asks Bill how many kids he has and their ages. "I have three daughters", says Bill, "the product of whose ages is 36 and the sum is the same as our house number". Tony thinks for a while and says that this is not enough information. Give me some more clues. On this, Bill says that the elder daughter plays the violin. With this information, Tony is able to tell the ages of Bill's daughters. Can you tell the ages of all the daughters of the Maths Professor?

Out-of-Box Thinking Mathematical Age Brain Teaser-Answer

VII) As the product of the daughters' ages is 36. Below are the number of combinations that make the product 36.

6+6+1 = 13 

4+3+3 = 10

9+4+1 = 14

2+9+2 = 13

2+3+6 = 11

Now, if the sum of their ages is unique, then Tony would have been immediately telling the ages of Bill's daughters. So the sum of their ages being 13 is not unique. Which leaves us with two choices. 

6+6+1 = 13 and

2+9+2 = 13

which are not enough to make any deductions. Now, when Bill says that his elder daughter plays the violin, it makes it clear that it has to be the elder daughter at age 9 who plays the violin, giving us the ages of Bill's daughters as 2, 2, and 9.

If you liked these Critical Thinking Brain Teasers, then you should also check more Mathematical and Logical Puzzles on this website, as mentioned below.

List of Maths and Logical Brain Teasers

Out-of-Box Thinking Fun Brain Teasers: It contains many different Mathematical as well as Logical Brain Teasers which will make you think out of the Box.

Simple Fun Brain Teasers for Kids: It contains very simple brain teasers which adults may find difficult to solve. However, if you think like a kid, then you will be able to solve these brain teasers very easily. In fact, these brain teasers will make you think like a kid.

Fun Brain Teasers to Challenge Your Mind: This is the most liked post on our website for the last many years. It contains all types of brain teasers which will challenge your mind.

Picture Puzzles with Answers: Most of the brain teasers mentioned till now test your Mathematical or Logical Mind. However, these are brain teasers to test your observational skills.

Nowadays, these types of Critical Thinking Brain Teasers also appear in interviews. So, solving these brain teasers will not only help students to score better marks in their exams but also people who want to appear in job interviews, especially in Information Technology (IT) based companies like Microsoft, Google, Facebook, etc. Write down your answers and feedback in the comments.

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