Brain Teasers
Hickory Dickory Clock
Hickory, dickory, dock, a mouse has messed up the clock. Something, at least, has messed up the old alarm clock in Randy's bedroom. Sometimes it runs backward, with the hands moving counter-clockwise.
When Randy looked at the clock yesterday morning, it showed a quarter to 10. It then ran backward for 14 hours, 6 minutes, and then forward for 5 hours, 53 minutes, and finally backward again for 10 hours, 41 minutes.
Randy's clock is a standard 12-hour analog clock.
What time will the clock now show?
When Randy looked at the clock yesterday morning, it showed a quarter to 10. It then ran backward for 14 hours, 6 minutes, and then forward for 5 hours, 53 minutes, and finally backward again for 10 hours, 41 minutes.
Randy's clock is a standard 12-hour analog clock.
What time will the clock now show?
Hint
Remember that in adding and subtracting minutes, there are exactly 60 minutes in an hour. Randy's clock shows only 12 hours.Answer
The clock will show 2:51, or 51 minutes after 2.In considering time, we have to think in units of 12 (hours) and 60 (minutes).
The clock showed 45 minutes after 9 when Randy first checked it.
After the first 12 hours of the 14 hours and 6 minutes of running backward, the clock was back at 45 minutes after 9. Then it ran back an additional 2 hours and 6 minutes to 39 minutes after 7.
After running forward for 5 hours and 53 minutes, the clock showed 32 minutes after 1.
After going backward again for 1 hour, the clock showed 32 minutes after 12. Then, after it ran back the remaining 9 hours and 41 minutes, it showed 51 minutes after 2.
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Comments
Tedious. Add the two 'backwards' times first and blow off 24 hours because clock laps itself every 12 and every multiple of 12.
yah, got it
Got it, but good 1.
Loved this one because when I was a child my grandmother had a clock. If you would unplug it from the means and then replug it sometimes it would run backwards.
Yes, tedious. Not much of a teaser.
I called it nine minutes to three, but same diff.
Also, since I have no confidence in my math, I was delighted.
Also, since I have no confidence in my math, I was delighted.
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