A man standing in front of a mountain beats a drum at regular intervals. The rate of drumming is generally increased and he find
s that the echo is not heard distinctly when the rate becomes 40 per minute. He then moves nearer to the mountain by 90 m and finds that echo is again not heard when the drumming rate becomes 60 per minute. The distance between the mountain and the initial position of the man is __________. A) 205 m
B) 300 m
C) 180 m
D) 270 m
