Question

total time for a rock drop from top of the well to the bottom and the sound bouve back is 5.6 sec, the well dept is 450 ft, true or false

Answer 1

The time to fall would be sqrt(2H/g)= 5.3 s (using g = 32 ft/s62) . The time for sound to get be heard is 450 ft/(speed of sound) = 0.4 s

I get a total time to hear the sound to be 5.7 s.

I am not sure if they would consider that good agreement (with 5.6 s) or not. Your call.