physics
posted by ajo .
A spelunker drops a stone from rest into a hole. The speed of sound is 343 m/s in air, and the sound of the stone striking the bottom is heard 1.50s after the stone is dropped. How deep is the hole?
how can i use the speed of sound to solve this problem?Please give me some hints!
Thanks a lot!

The time required to hear the impact is the sum of the time for the stone to fall and the time for the sound wave to reach the top of the hole.
If the hole depth is X,
1.50 seconds = sqrt (2X/g) + X/v
where v is the speed of sound and g is the acceleration of gravity.
Solve for X 
10.6m