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Today Puzzle #684

Puzzle No. 684– Wednesday 26 February 2020

The Bank of England has begun the massive task of destroying £40bn-worth of paper banknotes which have been replaced by new polymer £20 notes on Thursday. Two billion paper notes will be withdrawn and recycled to be used as a soil improver. Two huge high-speed note-sorting machines each sort 33 notes per second. How long will it take for all the notes to be processed?

Note: For this question a billion is a thousand million

Today’s #PuzzleForToday has been set by Dr Shaun Fitzgerald, Fellow of Girton College

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The time taken is 2,000,000,000 notes / (2 machines x 33 notes per second) = 30,303,030 seconds. This is 30,303,030 seconds / (3600 seconds per hour x 24 hours per day) = 350 days, i.e. about a year.

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