Replying to Calculus help

I know this isn't a homework help site but I need help on this and it's due today before midnight, so if anyone is good with calculus could you help me out? Thanks.

You drop a rock into a well (from ground level). You can't see the impact at the bottom but you hear it after 7.9 seconds. You wonder how deep the well is. Assume the speed of sound is 1100 feet per second and the acceleration of the rock is 32 feet per second squared. Ignore air drag (this is a major simplifying assumption).


(Hint: the time till you hear the impact is the sum of the time the rock takes to reach the bottom and the time the sound of the impact takes to travel back to your ear.)


The depth of the well (in feet) is?

Gah, that speed of sound deal is confusing me