Welcome to MindCipher, a social repository of the world's greatest brain teasers, logic puzzles and mental challenges.
3 1 What number is next?
What number comes next in this sequence? 4, 20, 56, 120, 220, ?
Submitted by Aakash
Doable
4.3
4 3 The Price Is Right
Many shops have prices set just under a round figure, e.g. $9.99 instead of $10.00 or $99.95 instead of $100.00 . It is assumed that this is done because the price seems lower to the consumer. But th ...
Submitted by Aakash
Hard
7.0
3 The fake coin
You have 9 coins which all look identical but 1 of them weight less than the others. You have a two pan balance (see the picture) with which you can measure twice, and with this 2 measurements you ha ...
Submitted by Aakash
Doable
3.5
4 2 What am I?
The first person makes me and sells me. The second person buys me but doesnt use me. The third person uses me but doesnt see me. What am I?
Submitted by Valentin
Hard
6.8
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
1 1 The fisherman and the Hunter
The are two men that always tell the truth except for the days when they are lying. The fisherman lies on Monday, Tuesday and Wednesday. The Hunter lies on Thursday, Friday and Saturday. Today the ...
Submitted by Valentin
Easy
3.0
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
0 4 Plane In The Wind
An airplane flies in a straight line from airport A to airport B and back. It has constant engine speed and no wind. Will its total flight time increase, decrease or stay the same if throughout bot ...
Submitted by Valentin
Doable
4.0
2 3 The Way Engineers Think
A priest, a doctor, and an engineer were waiting one morning for a particularly slow group of golfers. Engineer: What’s with these guys? We must have been waiting for 15 minutes! Doctor: I don’t ...
Submitted by Aakash
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
2 3 Marble Weights
You are given a set of scales and 12 marbles. The scales are of the old balance variety. That is, a small dish hangs from each end of a rod that is balanced in the middle. The device enables you to c ...
Submitted by Ravi
Hard
7.0
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
0 4 Cutting Numbers
When is Seven half of Twelve?
lateral thinking Submitted by Ravi
Easy
3.0
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
2 2 The Number Problem
What does 3685=? 8809=6 7111=0 2172=0 6666=4 1111=0 3213=0 7662=2 8096=5 9312=1 4444=0 6824=3 9999=4 0345=1 2359=1 5522=0 9884=5 Enjoy, this is quite interesting.
Submitted by Ravi
Doable
4.0