In Liar, Truth-teller, Random-Answerer Riddle, a traveler can ask two questions to decide which is the safe path out of two. What to ask?
4 Prisoners and Hats Puzzle: Alien chief offered a game of freedom or death to his 4 prisoners. Each will wear a hat and guess its color. Can anyone win?
How many addition signs should be put between digits of 987654321 to equal 99? Where should they be placed? Time to solve 10 minutes.
Cherry in the glass puzzle: Move 3 matchsticks to take the cherry out of wine glass. Second puzzle is harder: Move 2 matchsticks to take the cherry out.
9 squares puzzle: Find area of rectangle with 9 gradually smaller squares inside it and the side length of smallest square 3 units. Time 30 minutes.
In a difficult problem situation, use the negative force as a positive one to inventively achieve great success that all thought impossible.
Surely you can solve the 3 digit number puzzle in 20 mins if you approach the puzzle with systematic problem solving techniques.
In liar and truth-teller riddle, to know the safe path, a traveler can ask only one question to any one of a habitual liar or a truth-teller. What to ask?
Bridge Crossing Riddle: 4 persons to cross a bridge at night in 17 mins. Two persons can cross at a time with crossing speeds of each different. Read on...
Fox goose corn riddle: Farmer to cross river with fox, goose and corn in a boat that takes at most two. Fox eats goose and goose eats corn if left alone.
