ps 155 og 10

Question

A certain clock marks every hours 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 elaspe between the beginning of the first stroke and the end of the last stroke A 72 B 50 C 48 D 46 E 44 PLZ explain your work Thankssss

SunShine · Answer

D. 46 SEC.

for 6 o'clock the no of stokes are 6, number of interval =5, total 11, and tiem taken for each stroke and interval is same, therefor 22/11 =2 second

by same logic the number of stroke for 12 o'clock is 12, number of interval is 11, total 23, that means 23*2 = 46 seconds.

stretchad · Answer

I got D as well...2 seconds for each stroke, 2 seconds for each break between strokes. 23 strokes and breaks at 12, times 2 seconds = 46.

mand-y · Answer

plz can anyone tell me where this 23 comes from and is it 12 +11 ?
If yes why 


thanks

pmenon · Answer

Mandy, this comes from the example in the question .

The total time is the time per stroke plus the time interval between strokes. We are told that this is equal.

At 6 o clock, there will be 6 strokes. There will also be 5 intervals between strokes (1 between 1st and 2nd, 2 btwn 2nd and 3rd, 3 btwn 3rd and 4th, 4 btwn 4th and 5th, and 5 btwn 5th and 5th).

This is a total of 11 stokes/waiting periods that took a total of 22 seconds. Therefore, each stroke and waiting period lasts 2 seconds.

Apply the same logic for 12 o clock. There will be 12 strokes and 11 waiting periods of 2 seconds each. The total will be 12*2 + 11*2 = 46

I hope that helped.

ywilfred · Answer

We're told: time for each stroke = time between strokes. So if the clock strikes twice, then strike 1 = x, time between strike 1 and strike2 = x, and strike 2 = x. Total time = 3x.

At 6:00, the clock will strike 6 times. This is equal to 6 strikes + 5 in-betweens = 11x.

11x = 22 -> x = 2

At 12:00, the clock will strike 12 times with 11 in-betweens = 23x = 46.

Ans: D

mand-y · Answer

Thanks so much Pmenon it does !

ps 155 og 10

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