# At what time did John arrive home?

John has quite a curious clock at home. Every hour it rings a bell as many times as the number of hours (At 2 o´clock it rings twice, at 3 o´clock thrice and so on), and it rings only once at a quarter past, half past and quarter to whichever hour corresponds (For example, one ring at quarter past three, one at half past three, one at quarter to 4, and 4 rings at 4 o´clock).

One day he came back home, and as soon as he entered the house he heard one ring. After a while, he heard another one, and after a while another one, and so on until he heard one ring 8 times total. What time was it when he arrived home?

It was

shortly after 12 o'clock

when John arrived home.

When John walked in, he heard the last chime of the 12 o'clock bells, followed by three quarter-hour bells, then the single 1 o'clock bell, and finally three more quarter-hour bells, for a total of eight bells heard in isolation.

• If this isn't correct, then the real answer is instead that the bells heard were the three quarter-hour bells, then the 1 o'clock bell, then three more quarter-hour bells, then the first of two bells for the 2 o'clock bells. (presumably he was struck deaf right after). Pretty much the same answer but shifted in time slightly. Commented Mar 20, 2023 at 22:10

It was

Between Midnight and 1 AM on November 5th (or the day that DST ends) in a country that uses Daylight Savings Time! At exactly what would be 2 AM, the clock runs back to 1 AM and the ringing repeats the pattern for 1 ring being 1 AM. Thus this is a spread of time where there will be ELEVEN straight instances of only one ring in the clock's bells. Thus, He could have shown up at any moment between 12:01 AM and 1:00 AM, and would have heard eight straight instances of only one rung bell.

• Minor nitpick, not all countries make the switch at the same date or time. The EU is offset from the US by two weeks, and does a coordinated change which occurs at different local times across time zones. The general approach works anywhere with DST, but the specific date/time makes it applicable only in the US. Commented Mar 21, 2023 at 15:41
• Thanks for adding that, didn't know that. Commented Mar 22, 2023 at 16:40