Information

A problem with watches

A problem with watches

We have an analog clock that is delayed half a minute every day. Another clock of the same type instead stands.

Which will show the correct time more often?

Solution

The clock that is stopped will show the correct time twice a day. However, the clock that delays half a minute a day will take 2 × 60 × 12 = 1440 days to display the correct time, then the broken clock will mark the correct time more times.