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 10 Fork in the road You are walking down a road and arrive at a fork that splits the road into two separate paths. When you reach, you meet two identical twins, each standing at the edge of one of the two paths. You h ... Submitted by Aakash Doable 6.0 37 No if() Only abs() Given two variable a and b, construct a function f(a,b) which return the maximum one in {a,b}. You can only use +- · / and abs() (to take the absolute value). NO if() is allowed in your construction. ... Submitted by MoralMachine Doable 5.8 7 Cooking Time A cook must put a souffle exactly 9 minutes at the oven, but he only have a 7 minutes hourglass and a 4 minutes hourglass. How can he measure 9 minutes with those clocks? Submitted by Ravi Doable 5.7 12 Carpeting a Donut Given two concentric circles and a chord of the outer circle, tangent to the inner circle, of length 25m, find the area between the two circles. See illustration. No other information needed, all you n ... Submitted by Raymond Doable 5.5 1 Classic Knights & Knaves Raymond Smullyan has made a career of writing logic problems. His most famous have to do with a mythical island of Knights and Knaves. Knights always tell the truth, and Knaves always lie. As you a ... Submitted by Ravi Doable 5.5 9 The Monty Hall Problem You’re on a game show, and you’re given the choice of three doors: Behind one door is a car and behind the other two doors are goats. You pick a door, say No. 1, and the host, who knows what’s behind ... Submitted by Ravi Doable 5.5 3 The Cabin There is a man lying face-down, dead, in the middle of a cabin. The cabin is in the middle of the woods. There are windows, but they do not open. What is going on? Submitted by Valentin Doable 5.4 8 Attic Lamp Switch A downstairs panel contains three on-off switches. One of them controls the lamp in your attic. Using only ONE trip up to the attic, how do you determine which switch controls the lamp? Submitted by Valentin Doable 5.3 1 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 2 The Bookworm Looking onto a shelf you see three books each labeled Volume 1, Volume 2, and Volume 3 respectively. Each book is 2.5 inches thick; that is the pages are 2 inches, and each cover .25 inches. A bo ... Submitted by Aakash Doable 5.3 2 How far can you go? You have a 4 wheels car and a spare tire in the trunk. The tire being used will be worn off for 1/4 part of it per mile (completely wear out for 4 miles) How to make use of the spare tire to go as fa ... Submitted by MoralMachine Doable 5.2 1 Parodoxical Statements from Life Nobody goes to that restaurant; it’s too crowded. Don’t go near the water ’til you have learned how to swim. The man who wrote such a stupid sentence can not write at all. If you get this messa ... Submitted by Ravi Doable 5.2 4 Its waistline is a hexagon Heart of Darkness, Coat of Grain, Was once alive, Now feels no pain, Never walks, but Leaves a Trail. Circle head and pointed tail. Grows shorter as the day goes on- Its waistline is a hexagon. Wha ... Submitted by Valentin Doable 5.2 5 Sand Timer Puzzle You have two sand timers with you. One can measure 7 minutes and the other sand timer can measure 11 minutes. This means that it takes 7 minutes for the sand timer to completely empty the sand from one ... Submitted by Rohit Gurjar Doable 5.0 3 100 kg bag of potatoes if you have a 100kg bag of potatoes, that are 99% water, they're left out in the sun and dry up a bit, so it's now 98% water, how heavy is the bag of potatoes? Submitted by chuck3r Doable 5.0