GMAT数学题,
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