phsycs
posted by Adam .
A person shouts in a canyon. 3 s later they hear the echo. How far away is the canyon wall from which the sound wave was reflected?
how do i do this problem?

distance=velocity*time
2*canyonwidth=speedsound*time
solve for canyon widthhttp://www.ausetute.com.au/calcelemf.html 
2cw=340*3/2=510m but the answer given is 514.5m?

Sound waves move through air at sea level at a velocity of 343 m/s at 20ºC.
x=343•3/2=514.5 m 
50.7