Brain teasers, puzzles, riddles, and other challenges
These Wordle puzzles are nearly complete, you just need to finish them by figuring out the correct word. In each of these 5 puzzles, there should be just one or two valid answers remaining – find them!
Haven’t played Wordle before? You get 6 tries to guess the 5-letter English word, and for each guess you are shown whether each letter is in the right place in the word (green), in the word but in the wrong place (yellow), or not in the word at all (gray).
In the morbid game of Russian Roulette, a partially loaded revolver with a six-chamber cylinder is randomly spun, pointed at one of the players, and fired. If the revolver landed on an empty chamber, the lucky player is safe, and the process is repeated with the next player. The obvious objective of the game is to not get shot.
You find yourself stuck in a game of Russian Roulette. A freshly loaded revolver is aimed at the first player, and it turns out to be an empty chamber. Your turn is next, and you are given the choice to either:
Which choice should you pick if the revolver was originally:
Assume the revolver cannot misfire, and that spinning the cylinder lands on all chambers with equal probability.
Some variation of this Russian Roulette riddle was once asked in interviews at Jane Street, Susquehanna International Group (SIG), Facebook (now Meta), UBS, Capital One, and more.
Continue reading “Russian Roulette Riddle”Quick vocabulary puzzle – given the middle four letters of each word, figure out these 8-letter words:
| 13 | |||
| 10 | |||
| 4 | 16 | ||
| 7 |
The cells in this 4×4 grid puzzle contain the numbers 1-16 each once. There are two rules to the arrangement of the numbers:
Fill in the remaining numbers.
Continue reading “Consecutive Numbers Grid Puzzle”This puzzle was coined the “Impossible Puzzle” by Martin Gardner, a famous math and science writer that liked to create and write about math games and puzzles. The puzzle is named as such because it appears to provide insufficient information to solve, but it is in fact solvable! Read on for the puzzle and the (very difficult) solution.
There are two distinct whole numbers greater than 1, we can call them x and y (where y > x). We know the sum of x and y is no more than 100.
Sam and Prada are perfect logicians. Sam (“sum”) is told x + y and Prada (“product”) is told x * y, and both of them know all the information provided so far.
Sam and Prada have this conversation in which they truthfully deduce the numbers:
Can you figure out x and y using this information?
View SolutionForm four lines of four coins by moving exactly 3 of the coins below:
Rules:
Rearrange exactly 2 matches to make this a valid equation.
In matchstick math puzzles, you are not allowed to make an inequality symbol such as ≠, ≥, >, <, or ≤. That would make it too easy!
Continue reading “Matchstick Math 3”A truel is a three-way duel. The three participants take turns firing one shot at whichever opponent they choose, until only one is remaining.
Allison, Ben, and Chase are in a truel, and have varying degrees of accuracy: Allison has a 50% chance of hitting her intended target, Ben has a 80% chance, and Chase has a 100% chance. Allison gets to shoot first, then Ben, then Chase, and repeating in that order until only one person is remaining.
Assume that the accuracy of all participants are publicly known, and everyone is trying to maximize their chances of winning. What is Allison’s optimal strategy, and what is her likelihood of winning under that strategy?
Continue reading “Truel”
