OG-绿皮数学-P75,110题

chanyeen

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 begining og the first stroke and the end of the last stroke is 22 seconds. At 12:00, how many seconds 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.
希望大家给我讲解一下.