Masters of Logic ....... weighing games

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Q.1 There are 10 coin making machines. 9 out of them make coins weighing 1 gm each. One (unknown) machine is faulty and makes coins 100 mg heavier. You have an electronic weighing machine (single pan). Can you tell which machine is faulty by using the weighing machine only once?

Q.2 This one's not for kids. There are 12 coins. One of them is slightly heavier or lighter than the others. You have a classical balance with two pans (which only indicates which pan is heavier/lighter). You are allowed to weigh only three times. Can you find out the coin which is different, and also whether it's heavier or lighter? Discussion Solution

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