Welcome to MindCipher, a social repository of the world's greatest brain teasers, logic puzzles and mental challenges.
7 2 The bus stop
You’re driving your car to work in the pouring rain when you see three people on the side of the road at an uncovered bus stop. You recognize one as your best friend waiting to go to work, the second ...
Submitted by Aakash
Doable
4.7
2 2 Farmer's Market
You’re a farmer. You’re going to a market to buy some animals. On the market there are 3 types of animals for sale. You can buy: Horses for £10 each, goats for £1 each and ducks, you get 8 of these ...
Submitted by Aakash
Doable
4.7
4 5 Attic Light Switch
A downstairs panel contains three on-off switches. One of them controls the lamp in your attic. Using only ONE trip up to the attic, how do you determine which switch controls the lamp?
Doable
4.7
4 4 Microsoft Interview Question - Count it Out
This problem is more targeted towards people with Computer Science or similar backgrounds, it is a REAL question from an interview with Microsoft. You have an array of 99 unique numbers from 0-100. ...
Submitted by Aakash
Doable
4.9
5 3 Don't Eat Me!
Would you rather a crocodile attack you or an alligator?
Submitted by Aakash
Doable
4.9
9 1 Unfair Coin
Say you have an unfair coin: a coin whose probability of flipping heads and flipping tails is unknown but nonzero. Can you design a game where you and your opponent have an equal chance of winning?
Doable
5.0
1 3 Greatest Area
A farmer challenges an engineer, a physicist, and a mathematician to fence off the largest amount of area using the least amount of fence. The engineer made his fence in a circle and said it was th ...
Submitted by Valentin
Doable
5.0
4 5 Boys and Girls
To help solve an acute national over-population problem, a government issues a radical decree that families must stop having children as soon as they have had one son. After a while, there are some ...
Doable
5.0
4 3 Divide 1 to 20
What is the smallest whole number that can be divided by any number from 1 to 20 (inclusive) and not leave a remainder? For example, 60 is the smallest number that can be divided evenly by all the n ...
mathematics Submitted by Aakash
Doable
5.0
3 7 100 kg bag of potatoes
if you have a 100kg bag of potatoes, that are 99% water, they're left out in the sun and dry up a bit, so it's now 98% water, how heavy is the bag of potatoes?
Submitted by chuck3r
Doable
5.0
5 4 Sand Timer Puzzle
You have two sand timers with you. One can measure 7 minutes and the other sand timer can measure 11 minutes. This means that it takes 7 minutes for the sand timer to completely empty the sand from one ...
Submitted by Rohit Gurjar
Doable
5.0
1 8 Parodoxical Statements from Life
Nobody goes to that restaurant; it’s too crowded. Don’t go near the water ’til you have learned how to swim. The man who wrote such a stupid sentence can not write at all. If you get this messa ...
paradox Submitted by Ravi
Doable
5.2
2 4 How far can you go?
You have a 4 wheels car and a spare tire in the trunk. The tire being used will be worn off for 1/4 part of it per mile (completely wear out for 4 miles) How to make use of the spare tire to go as fa ...
Submitted by MoralMachine
Doable
5.2
4 3 Its waistline is a hexagon
Heart of Darkness, Coat of Grain, Was once alive, Now feels no pain, Never walks, but Leaves a Trail. Circle head and pointed tail. Grows shorter as the day goes on- Its waistline is a hexagon. Wha ...
Submitted by Valentin
Doable
5.2
1 3 Stuck in a brick building
A man is stuck inside an all brick building (floor, ceiling, and walls are all brick), that has no windows and no doors, and inside with him he has only a wooden board and a saw, how does he get out? ...
Submitted by Valentin
Doable
5.3