At 6:00 the time lapse between the beginning of the first stroke and the end of the second stroke is 22 seconds.

Did you correctly copy the question? If the time between the start of first and end of second is 22, then it means
Time to complete first stroke + interval + Time to complete second stroke = 22
n+n+n = 22
n = 22/3 = time for each stroke (or time lapse between strokes). Using this, none of the answer choices yield the correct answer.



However, assuming you meant At 6:00 the time lapse between the beginning of the first stroke and the end of the second stroke is 22 seconds.
At 6, there would be 6 strokes and 5 interval between strokes.
Total time = 11n = 22
n = 2
At 12, there would be 12 strokes and 11 intervals.
Total time = 23n = 46.

Answer is D.