time keeper

posted by Ragib
- April 14 2011 04:53:52 AM

you have two clocks.one of them is slightly faster than other one.there is no other time keeping device in the whole world.how do you know which is the right one?you are in a room having no way out or none to help you.assume that being in that room will still keep you healthy enough to solve it!i will give you a clue.one of the clock is 1.25-1.30 times faster than other one.

Reply by Caprico
- April 14 2011 08:57:24 AM

My method is a bit long, but I think it should suffice.

If one of the clocks is 1.25 times faster than the other (suppose), That means that for every 100 seconds of one corresponds to 125 seconds of the other. Now you wait as long as it take for the clocks to show the same time. When they do this, you'll know that one of the clocks is exactly one day ahead of the other. You should keep track as to which clock has shown how many days. Now obviously you can count the actual number of days that have passed till that happens, as that doesn't require any device. Thus you'll know which one is right.

If one of the clocks is 1.25 times faster than the other (suppose), That means that for every 100 seconds of one corresponds to 125 seconds of the other. Now you wait as long as it take for the clocks to show the same time. When they do this, you'll know that one of the clocks is exactly one day ahead of the other. You should keep track as to which clock has shown how many days. Now obviously you can count the actual number of days that have passed till that happens, as that doesn't require any device. Thus you'll know which one is right.

Reply by Ragib
- April 14 2011 09:49:50 AM

you actually need at most 5 minutes.as you are healthy enough,you should have 72 pulses per minute.the right one would measure 72 pulses in around 60 seconds.but the wrong one would take 48 or 90 seconds.it's unusual.

Reply by Caprico
- April 15 2011 08:41:45 AM

Wow, that's ingenious... Using your own body clock in a sense to check time... Nice...

Reply by Ragib
- April 15 2011 10:51:01 AM

the riddle is my creation:p

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