A certain clock marks every hour by striking a number of : GMAT Problem Solving (PS)
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# A certain clock marks every hour by striking a number of

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A certain clock marks every hour by striking a number of [#permalink]

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17 Feb 2011, 09:30
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A certain clock marks every hour by striking a number of times equal to the hour, and the time require for a stroke is exactly equal to the time interval between strokes. At 6:00 the time lapse between the beginning of the first stoke and the end of the last stroke is 22 seconds. At 12:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke?

A. 72
B. 50
C. 48
D. 46
E. 44
[Reveal] Spoiler: OA

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17 Feb 2011, 09:40
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Baten80 wrote:
A certain clock marks every hour by striking a number of times equal to the hour, and the time require for a stroke is exactly equal to the time interval between strokes. At 6:00 the time lapse between the beginning of the first stoke and the end of the last stroke is 22 seconds. At 12:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke?

a. 72
b. 50
c. 48
d. 46
e. 44

At 6:00: 6 strokes + 5 intervals between strokes = 11 parts = 22 seconds. So, 1 stroke = 1 interval = 22/11 = 2 seconds;

At 12:00: 12 strokes + 11 intervals between strokes = 23 parts * 2 seconds for each = 46 seconds.

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02 Mar 2011, 05:18
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Merging similar topics.
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A certain clock marks every hour by striking a number of tim [#permalink]

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13 Apr 2012, 02:09
A certain clock marks every hour by striking a number of times equal to tht hour and the time required for a stroke is exactly equal to the time interval between strokes. at 6.00 the time lapse between the begining of the first stroke and the end of the last stroke is 22 secs.at 12.00 how many secs elapse between the begining of the first stroke and the end of the last stroke ??

(A) 72 (B) 50 (c) 48 (d) 46 (e) 44...OA is D.. Wat is the solution ?
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Re: A certain clock marks every hour by striking a number of tim [#permalink]

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13 Apr 2012, 04:12
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Let x = time required for each stroke = time interval between strokes

Therefore when the clock strikes 6:00pm, the time requires for the six strokes = 6x (for the strokes) + 5x (for the interval between the strokes) = 11x = 22 secs
=> x = 2 seconds

Therefore at 12:00, time between the beginning of the first stroke and end of the last = 23x (12x+11x) = 46 seconds or option (D).
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Re: Arithmetic operation QR: 110 [#permalink]

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14 Apr 2012, 00:05
Baten80 wrote:
A certain clock marks every hour by striking a number of times equal to the hour, and the time require for a stroke is exactly equal to the time interval between strokes. At 6:00 the time lapse between the beginning of the first stoke and the end of the last stroke is 22 seconds. At 12:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke?

a. 72
b. 50
c. 48
d. 46
e. 44

from above information.... time for a stroke is 2s ( given info of 6Pm stroke)

for 12Pm stroke...it will stroke for 12 times and 11 times it is stil...so it is 23 spots... so 23 * 2 = 46 which is D
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Re: A certain clock marks every hour by striking a number of [#permalink]

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15 Apr 2012, 18:22
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Dear lord

Can someone explain what the question is even asking!

What the heck does this even mean!

"A certain clock marks every hour by striking a number of times equal to the hour"

Please can someone elaborate. Why does GMAC phrase questions like this?
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Re: A certain clock marks every hour by striking a number of [#permalink]

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15 Apr 2012, 23:22
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alphabeta1234 wrote:
Dear lord

Can someone explain what the question is even asking!

What the heck does this even mean!

"A certain clock marks every hour by striking a number of times equal to the hour"

Please can someone elaborate. Why does GMAC phrase questions like this?

It just means that at 1:00 the clock strikes once, at at 2:00 the clock strikes twice, at 3:00 the clock strikes 3 times, ...

Hope it's clear.
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01 May 2012, 01:24
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abhi47 wrote:
A certain clock marks every hour by striking a number of times equal to the hour and the time required for a stroke is exactly equal to the time interval between strokes. At 6.00 the time lapse between the beginning of the first stroke and the end of the last stroke is 22 seconds. At 12.00 how many seconds elapse between the beginning of the first stroke and the end of the last stroke ?

A) 72 B) 50 C) 48 D)46 E) 44

Please explain different ways to solve this problem

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Re: A certain clock marks every hour by striking a number of [#permalink]

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01 May 2012, 01:40
Thanks for merging.
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Re: A certain clock marks every hour by striking a number of [#permalink]

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03 Jun 2012, 05:52
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alphabeta1234 wrote:
Dear lord

Can someone explain what the question is even asking!

What the heck does this even mean!

"A certain clock marks every hour by striking a number of times equal to the hour"

Please can someone elaborate. Why does GMAC phrase questions like this?

the question of WHY the GMAC made this kind of weird of question is a mystery...... you should ask to them.

But I agree with you: for non native understand only what the problem wants sometimes is difficult. I came to the solution, however before to understand that the problem simple says: for instance at 12 o'clock we have 12 strokes or dolls..........those are the rules in gmatland
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Re: A certain clock marks every hour by striking a number of [#permalink]

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28 Aug 2012, 19:13
I don't understand the interval part in the explanations. How do you come up with 5 intervals? Why do you add them together?
Thanks.
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Re: A certain clock marks every hour by striking a number of [#permalink]

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28 Aug 2012, 21:39
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bohdan01 wrote:
I don't understand the interval part in the explanations. How do you come up with 5 intervals? Why do you add them together?
Thanks.

I guess your generation has had no exposure to the clocks of the old days.
In the old days, the clocks used to strike at the hour i.e. at 2 o clock, you would hear 2 strikes. There would be a small interval between two strikes. The point was that watches/clocks were not common and often there was a single clock for a whole village. There would be loud strikes at every hour to inform everyone of the time. People could count the strikes to know what time it is.

Check out this youtube video of big ben to understand what a clock strike is: http://www.youtube.com/watch?v=rkXy20fUoic

at 6'o clock, there would be 6 strikes. First strike, then a short interval, the second strike, then a short interval and so on till the 6th strike. So there would be in all 5 intervals between 6 strikes. Similarly, between 12 strikes, there would be 11 intervals.

According to the question, the time spent in the strike and the interval is same.
At 6'o clock, the 6 strikes and the 5 intervals together take 22 sec so each strike and each interval takes 2 secs.

At 12'o clock, the 12 strikes and 11 intervals will take 2*(12+11) = 46 secs
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Re: A certain clock marks every hour by striking a number of [#permalink]

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29 Aug 2012, 17:40
Karishma,
I have to say, that was a great explanation. Thank you. Although this question sounds like 500-600 level, the difficulty in understanding it makes it impossible for me to answer it correctly without getting lucky! Oh well, hope nothing similar appears on the actual exam.
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Re: A certain clock marks every hour by striking a number of [#permalink]

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31 Aug 2013, 10:19
Thanks Karishma...makes it so much clearer
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Re: A certain clock marks every hour by striking a number of [#permalink]

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24 Feb 2014, 16:51
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Such a poorly worded question, I got 99th percentile on verbal and I still wasn't sure what the question asks for.
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Re: A certain clock marks every hour by striking a number of [#permalink]

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24 Feb 2014, 19:23
This is a kind of question where you read a sentence and then get frustrated. Its hard to interpret in first read and because of frustration while re reading we don't pay much attention.
The point here is to not get frustrated and understand its a mind game. So take a deep breath and read again.

Also, believing in yourself is necessary. After reading you might doubt "Is what I interpret is actually what question asking?" Just believe in yourself (at least during practice) and think it is exactly what question is asking.

When you are a manager, you might have to deal with a person with a very irritating nature. Its takes a lot to patiently deal with such a person. I relate this question with those people
That's what GMAC might want to see in you :D
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Re: A certain clock marks every hour by striking a number of [#permalink]

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24 Feb 2014, 22:41
OPEN DISCUSSION OF THIS QUESTION IS HERE: a-certain-clock-marks-every-hour-by-striking-a-number-of-tim-167784.html
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Re: A certain clock marks every hour by striking a number of   [#permalink] 24 Feb 2014, 22:41
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