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 7:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke?  Choose the correct choice: A) 26 B) 29 C) 19 D) 30 E) 40
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 7 strikes, there would be 6 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.   26t 7'o clock, the 7 strikes and 6 intervals will take 2*(7+6)= 
<gadget id="calculator">2*(7+6)</gadget>
<output>26</output>
26 secs   26
<result>A</result>
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 7:00, how many seconds elapse between the beginning of the first stroke and the end of the last stroke?