How to solve this is there a formula ?

Question

The speed of sound is normally 1080 ft/sec. John black stands on an observation deck and yells down a canyon. If he hears his echo 1.7 seconds later, how deep is the canyon to the nearest foot?

Answer 1

The formula is:

 

distance = rate × time.

The sound must echo off the canyon floor and return to the listener, so the distance traveled during the 1.7 seconds is twice the depth of the canyon. Therefore, we have

2 × depth = rate × time

 

depth = rate × time/2

         = 1080 ft/s × 1.7 s × 0.5

         = 918 ft.