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Today Puzzle #774

Puzzle No. 774– Thursday 2 July

In a pile of 200 coins, 2% are gold coins and the rest are silver. Simon removes one silver coin every day until the pile contains 20% gold coins. How many silver coins does Simon remove?

Today’s #PuzzleForToday has been set by Senior Kangaroo mathematics competition, run in the UK by the UK Mathematics Trust.

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180

The number of gold coins in the original pile is 0.02 x 200 = 4. These form 20% of the final pile. Therefore there are 4 x 5 = 20 coins left. Hence the number of silver coins Simone removes is 200 – 2- =180

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