## Saturday, May 9, 2020

In our daily life, we come across many different problems. For some of these problems at the beginning, we may think that these problems are impossible to solve. However, if we thinking critically and deeply then we can find the solution to these problems easily. During our student life also we come across many such critical thinking brain teasers where we need to do many different mathematical calculations or think very logical to find the solution of the given brain teasers. Here are such critical thinking brain teasers to challenge your mind.
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 puzzle statement which at first instance may look like 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 carefully 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.

## Mathematical Gold Coins Weight Puzzle

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

## 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 the 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 lights 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 divide the pearls to increase your chances of survival?

## 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?

## 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 Red Pill and another is 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 pill 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 colour of the pills. How he will make sure that he consumes one blue pill and one red pill to become a superman and then escape. Do remember that if he consumes two Blue or Two Red pills at the same time, he will die immediately.

## 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 the Bill, "the product of whose ages is 36 and sum is the same as our house number". Tony taker thinks for a while and says that these are not enough information. Give me some more clues. On this Bill says that 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 Maths Professor?

If you liked these Critical Thinking Brain Teasers, then you should also be checking 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 Box.
• Simple Fun Brain Teasers for kids: It contains very simple brain teasers which adults may find it difficult to solve. However, if you think like as 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 from 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 appears in the interviews. So solving these brain teasers which not only will help students to score better marks in their exams but also to the people who want to appear in job interviews especially in the Information Technology (IT) based companies like Microsoft, Google, Facebook etc. Let us see how many of these brain teasers you were able to solve correctly. Answers of these Critical thinking brain teasers are given as below

Coins Logical and Mathematical Brain Teaser Solution
I)As the total number of coins is 11. In case B is given more than 4 coins then his answer will 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 ask C.
So, B is having a minimum of 2 coins. C could have said NO if he is having 2 or less. So C is having either 3 or 4 coins.
D can only say this statement if he is given 5 coins. Now D having 5 coins remaining 6 coins can be divided into others as A=1, B=2 and C=3.

Mathematical Gold Coins Weight Puzzle Solution
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 the bag marked 2, 100 coins from the bag marked 100 and so on. Put all the coins together and weigh them together.
If there no bag containing the coins which 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 = 5050gms. However, it will weigh higher than this say by amount X. So the bag number which contains gold coin 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 weighs more than other gold coins.

Switches Out of Box Thinking Brain Teaser Solution
III) This 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 bulb which is ON linked to switch B. The bulb which 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 Solution
IV) This is the probability-based puzzle. In this, you have to maximize the probability of your survival. In order 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 White Pearl
Put one White Pearl in One box and remaining 99 Pearls in another box.
Now the probability of your survival is maximized. Suppose you pick up the box which has only one White Pearl which is 0.5 or 50% probability. So you survive in this case
Another case you pick up the box which has a mix of both the White and Black Pearls. In this case, your probability of getting white Pearl is 49/99 which is 0.495. So you total probability of survival is 0.500 + 0.495=0.995 i.e. 99.5%.

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 keys lie in the word "ALL".
1st logician wants the drink otherwise his answer to this question will "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 answer, 2nd Logician can deduct that 1st one wants a drink and 2nd Logician also wants a drink but he was not sure of the third one. So he answers "I don't know". Now the 3rd one wants the drink and from the previous answers, he could deduct that the other two also wanted the drink. This is the reason he answered "Yes".

Great Logical Blue and Red Pill Brain Teaser Solution
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 Solution
VII) As the product of the daughters' ages is 36. Below are the number of combinations which makes 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 the elder daughter with age 9 which plays the violin giving us the age of Bill's daughter as 2, 2 and 9.

1. Interesting puzzles. Keep up good work!

1. It is nice to know that you liked these puzzles and brain teasers. Please share it with your friends.

2. The answer to the 1st one is incorrect. C cannot have 2 because if C had 2, C cannot have more than B so C would answer No to B's question. The answer therefore is A=1, B=2, C=3, D=5.

1. You are right. Thanks for your comment, I have updated the correct solution to the 1st puzzle. Thanks for pointing it out and helping us to improve our website.

3. I was about to write a comment, that the answer to the riddle no. 1 is wrong, but someone has already noticed it.

1. Sorry I missed updating the correct answer when it was pointed out earlier. Thanks to your comment, I corrected the answer and explanation to the 1st critical thinking puzzle. Thanks for helping us to correct these mistakes.

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