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 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 10 Mutilated Chessboard Problem Suppose a standard 8×8 chessboard has two diagonally opposite corners removed, leaving 62 squares. Is it possible to place 31 dominoes of size 2×1 so as to cover all of these squares? Submitted by Ravi Hard 7.8 8 The Famous Hole in a Sphere This incredible problem was first made famous by Martin Gardner with his ‘Mathematical Games’ column published in Scientific American throughout the 60s and 70s. A cylindrical hole, 6 inches long, ... Submitted by Ravi Hard 6.7 7 Bug's Eye You are a bug sitting in one corner of a cubic room. You wish to walk (not fly) to the extreme opposite corner – the corner furthest from you. Describe the shortest path that you can walk. Submitted by Ravi Doable 3.8 4 Don't Hang Yourself A fool wants to tie a rope around the earth. So he buys a rope of 40,000 KM and ties it around the world. His neighbour, also a fool, wants to do the same only he wants the rope on sticks 1 meter abo ... Submitted by Valentin Easy 3.1 2 The North Pole Bear Puzzle Reloaded A man walks 1 mile south, then 1 mile east, and finally 1 mile north to find himself in exactly the same position as he started. He is NOT at the north pole, nor does he shoot a bear. Where is he? ... Submitted by Ravi Doable 6.0