20 claps equal 50 secs
1 clap
We cross multiple
1 clap×50claps / 20 claps
So 1 clap takes 2.5 secs
For one to hear an echo sound will travel up to the wall then back hence travellings 400×2=800metres
From our formulae distance=speed×time
800=s×2.5
Hence speed=800/2.5
=320m/s
Rootz answered the question on October 28, 2017 at 18:22
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