A cowboy stands on horizontal ground between two parallel vertical cliffs. He is not midway between the cliffs. He fires a shot and hears its echoes. The second echo arrives 1.84 s after the first and 1.63 s before the third. Consider only the sound traveling parallel to the ground and reflecting from the cliffs. (Take the speed of sound as 343 m/s.)
(a) What is the distance between the cliffs? m
(b) If he can hear a fourth echo, how long after the third echo does it arrive? s