# You have the misfortune to own an unreliable clock. This one gains exactly.................what is the correct time now?

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You have the misfortune to own an unreliable clock.
This one gains exactly 12 minutes every hour.
It is now showing 10 pm and you know that it was correct at midnight, when you set it.
The clock stopped four hours ago, what is the correct time now?

posted Aug 19, 2019

10:20 pm

The clock is gaining 12 minutes every hour --> for every real hour that has passed, the clock will show 72 minutes.
The clock shows 10:00 pm = 22:00 hrs, so 22 x 60 = 1320 clock minutes have passed. (1320 / 72) x 60 = 1100 real minutes =
=18 hours 20 minutes = 6:20 pm.
The clock stopped 4 hours ago, therefore the time must now be 10:20 pm

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