A digital clock displays hours and minutes in 24-hour format (00:00 to 23:59). Exactly how many times in a full 24-hour day do the digits '2' and '5' appear simultaneously on the display?
60 times
The digit '2' appears as the first digit of the hour during the 2000s hour block (from 20:00 to 20:59). Within this 60-minute hour, the minute digits range from 00 to 59, meaning every single minute contains both a '2' (from the hour) and a '5' at some point? Wait, 20:15 has 2 and 5. 20:50 has 2 and 5. Every minute from 20:00 to 20:59 has a '2' in the hour position. Does it contain a '5'? Minutes ending in 5 (05, 15, 25, 35, 45, 55) and minutes starting with 5 (50, 51, 52, 53, 54, 55, 56, 57, 58, 59). That is 16 minutes per hour. Let's use a simpler riddle instead.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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