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There are 1 red, 2 orange, 3 green, 4 blue, 6 yellow socks in a drawer kept in a room. Find the minimum number of socks you need to take out so that at least one pair of socks is there.
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There are 12 balls out of which 11 are same weight and 1 ball has weight that keeps on changing (but never equal to same weight balls). You have a double-pan balance scale. Find the minimum number of times you need to weigh to get the ball with different weight.
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There are 10 sacks. 9 of them contain 1 gm coins. 1 contains 1.1 gm coins. You have the digital weight. Find the number of times you need to weigh to get the bag which contains 1.1gm coins.
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You have 2 jars with capacity of 5 litres and 3 litres which can be filled with water. Using these 2 only, measure 4 litres of water.
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There are 25 horses among which you need to find out the fastest 3 horses. You can conduct race among at most 5 to find out their relative speed. At no point you can find out the actual speed of the horse in a race. Find out how many races are required to get the top 3 horses.
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You are blindfolded and 20 coins are place in front of you on table. You are allowed to touch the coins, but can’t tell which way up they are by feel. 10 coins are placed heads up and 10 are placed tails up. How do you make two piles of coins each with the same number of heads up? You can flip the coins any number of times.