Welcome to MindCipher, a social repository of the world's greatest brain teasers, logic puzzles and mental challenges.
0 5 The Twiddled Bolts
Two identical bolts are placed so that their helical grooves intermesh. If you move the bolts around each other as shown in the picture, would they a) move inward b) move outward c) remain the same d ...
Submitted by Valentin
Doable
6.0
5 15 Crazy Google Interview Question
You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving ...
Doable
6.0
2 1 What Am I?
Give me food, and I will live Give me water, and I will die What am I?
Submitted by Aakash
Doable
6.0
1 Neat twist on hat problem!
There are 100 people standing in a circle. Each person is given one hat to wear. A hat is either colored red or blue. A person cannot see his own hat color, but he can see the colors of the hats of all ...
logic Submitted by Simon
Doable
6.0
3 3 Open Water
A man is in a rowing boat floating on a lake, in the boat he has a brick. He throws the brick over the side of the boat so that it lands in the water. The brick sinks quickly. The question is, as a r ...
Submitted by Valentin
Doable
6.0
5 8 Lab Rat on the Run
Consider a lab rat in a maze. There are four paths that can be taken with equal probability. Path A leads to exit in 5 minutes. Path B leads back to start and takes 8 minutes. Path C leads to exit in 3 ...
Doable
6.0
0 4 Don't be a Square
Shown is a large square made up of four shapes, and a separate square, labeled with an E. Using all five of the shapes (A through E) only once, can you form a second perfect square?
Submitted by Aakash
Doable
6.0
4 6 Cut the pizza into 11 equal slices with a wrist watch
Tools: (1) A wrist watch and (2) a normal knife Goal: Slice a pizza into 11 equal pieces
Doable
6.0
3 6 Tooth Paste, : Profit
There are 2 Persons, Who Saves Money. One person Bought a tooth Paste of 100 gms, for Rs. 40. The second person Buys, Two 50 gms for Rs. 20 each. at same shop, the same company of Pastes. No Extra past ...
Doable
6.0
2 6 The North Pole Bear Puzzle Reloaded
A man walks 1 mile south, then 1 mile east, and finally 1 mile north to find himself in exactly the same position as he started. He is NOT at the north pole, nor does he shoot a bear. Where is he? ...
brain teaser geometry Submitted by Ravi
Doable
6.0
1 4 3 Painted Ladies
There are 3 smart old ladies standing in a desert such a way that each lady can see the other two. Each of the 3 ladies has paint on her face. Seeing this, all three ladies begin laughing. After a wh ...
Submitted by Ravi
Doable
6.0
5 2 Age of Three Kids
One day, a guy from census come into a house. When he rings the bell, a lady comes out. He then asks how many people lives in her house, and their age. And then she says: I am 45 years old. I have thr ...
Doable
6.0
6 2 Salary
Three coworkers would like to know their average salary. how can they do it, without disclosing their own salaries.
Submitted by Aakash
Doable
6.0
5 3 Cards With Crosses
You have a stack of 23 cards. Each card has an image of a cross on one side, and an image of a circle on the other side. You know that 14 cards in the stack are laying with the cross up, and therefor ...
Submitted by Valentin
Doable
6.0
14 80 Coin Flip
On Monday, you flip a coin all day. You start flipping it until you see the pattern Head, Tail, Head. You record the number of flips required to reach this pattern, and start flipping again (and co ...
Math statistics Submitted by Aakash
Doable
6.0