Honkai: Star Rail features a number of interesting logic puzzles in its quests. One side quest has you questioning suspects to determine the detector thief. Similar to some classic “who is lying” logic puzzles that you might have encountered before! Here is the Honkai Star Rail detector thief puzzle, and how to solve it: Who is the detector thief? You interrogate the four suspects, and each makes one claim: Cook says the helper did it Tailor says it wasn’t her Merchant says the cook did it Helper says it wasn’t him Swetta also tells you a critical piece of information: only one of the suspe ..read more

If you have me, you want to share me. If you share me, you haven’t got me. What am I? Click to show solution to “If you share me you haven’t got me” A secret Many people who have a secret want to share it. But if you share a secret, it is no longer secret, so you haven’t got it anymore ..read more

A detective is called upon to solve the riddle of the mystery killer in a high-profile murder. There are only three suspects: Aaron, the best friend Patty, the gardener Jason, the neighbor The victim was holding a calendar, and it seems he marked several of dates before he passed away: the second of January, the sixth of February, the third of April, the fourth of October, and the first of November. With this information, the detective identified the culprit. Who was it? Click to See Solution to Mystery Killer Riddle Aaron The calendar was marked such that each day refers to the position of ..read more

In a certain classroom, 75% of the students can speak English, 55% of the students can speak French, and 10% speak neither language. What percentage of the students speak both languages? Click to reveal solution 40% You can think of the whole group of students as comprising the 75% of students that speak English, the 55% of students that speak French, minus the x% of students that speak both languages (because this group has already been counted twice, we subtract to avoid double-counting), plus the 10% the speak neither: 100 = 75 + 55 – x + 10 Solving this equation gives us x = 40 ..read more

The Monty Hall Problem You are on a game show in which there are three identical doors, one with a car behind it and two with goats behind them. You must pick one door, and you win if that door has the car behind it. After you pick a door, the host of the game show always opens a door you didn’t choose that has a goat behind it. This leaves the door you chose and one other remaining door, and you are given the option to switch your choice to the other remaining door. Should you switch or should you stick to your original choice? What chance of winning would that give you? The History The Monty ..read more

Move exactly 2 matches to make this a valid equation. Bonus: find two different solutions. In matchstick equation puzzles, you are not allowed to make an inequality symbol such as ≠, ≥, >, <, or ≤. That would make it too easy! Solution 9 – 1= 8 or 2 + 7 = 9 ..read more

White to play and mate in 2. Solution Qh3 If 1. … Rxh3, then 2. Rxh3# If 1. … Nxh3 or Ne2, then 2. Rf1# If 1. … Nxf3, then 2. Qf1 ..read more

If a triangle has two sides with lengths 3 and 4, what should the length of the third side be in order to maximize the area of the triangle? Solution 5 Using Calculus This is the type of problem that calculus was designed to solve: If a triangle has side lengths a and b, and the angle between them is θ, then the area of the triangle is ab sinθ To find the maximum, find the value of θ such that the derivative of the area is equal to zero: (ab sinθ)’ = ab cosθ = 0 There are multiple solutions, but only 90° is a valid solution for an angle of a triangle – therefore it’s a right triangle and the ..read more

Compound words are words that are composed of two or more other words, like high + light = highlight. Can you make compound words out of the following three words by adding the same 4-letter word either before or after each word? CROSS WORKS WILD Solution Add “FIRE”: CROSSFIRE FIREWORKS WILDFIRE ..read more

Prove that for all prime numbers p > 3, (p2 – 1) is a multiple of 24. Solution First, factor the expression: p2 – 1 = (p + 1) (p – 1) Among any 3 consecutive numbers, one must be a multiple of 3. Since p is a prime number greater than 3, p is not a multiple of 3. Therefore, either p + 1 or p – 1 must be a multiple of 3, which means (p + 1) (p – 1) is a multiple of 3. Since p is a prime number greater than 3, p is odd and both p + 1 and p – 1 must be even. Among any two consecutive even numbers, one must be a multiple of 4 and the other must be a multiple of 2. Therefore (p + 1) (p – 1) is ..read more