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April 9, 2009

Clock Puzzles



If a clock takes 7seconds to strike 7, how long will the same
clock take to strike 10?

6 comments:

philofsci said...

3 seconds.

so it takes 1 second for every "hour"
7 seconds to get from 12 to 7. and since it's already on 7 ("the same clock") it only has 3 to go to get to 10.

Secret Squïrrel said...

I think the question is asking how long it will take a clock to chime 10 times to indicate that it is 10 o'clock.

If it takes seven seconds to strike 7 and we start timing at the beginning of the first strike, then the gap between each strike is 7 / 6 seconds.

There will be 9 intervals when striking 10 so it will take (10 * 7) / 6 = 11 2/3 seconds.

Anonymous said...

No it will be 9*7/6 seconds.

Secret Squïrrel said...

Gah! I am a numbnut. I said 9 intervals and then plugged 10 into the equation. (Works out to 10.5 s)

Note to self: always check your work before handing it in

Anonymous said...

363 seconds til the clock has struck 10
or is that 56 seconds
or maybe 115 seconds

ElatedSipun010 said...

Ans: 17 seconds
Explanation:
Lets think about the second hand.
If it takes 7 seconds to reach 7 then initially it was at 2 ticks(2 seconds before 6).So from 7 it will take 15 ticks(i.e.7 seconds) to reach at 10 while from the initial point it will take 10+7 = 17 seconds to reach 10.