Sunday, July 14, 2013

IPM mega finals STD IV answer

An electronic digital watch shows 20:07. What time should pass at the earliest after which the same digits apppear again in a different order?


checking the combinations in ascending order.
00.27
00.72
02.07
02.70
07.20
07:02

So, 00:27 is the time when all digits will reappear for the first time.
therefore, 00:27 - 20:07 = 4 hrs 20 mins will pass at the earliest.

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