You drop a rock into a deep well. You can't see the rock's impact at the bottom, but you hear it after 5 seconds. The depth of the well is _________ feet. Ignore air resistance. The time that passes after you drop the rock has two components: the time it takes the rock to reach the bottom of the well, and the time that it takes the sound of the impact to travel back to you. Assume the speed of sound is 1100 feet per second.
Note: After seconds the rock has reached a depth of feet where

Set up and solve a quadratic equation.

Question

You drop a rock into a deep well. You can't see the rock's impact at the bottom, but you hear it after 5 seconds. The depth of the well is _________ feet. Ignore air resistance. The time that passes after you drop the rock has two components: the time it takes the rock to reach the bottom of the well, and the time that it takes the sound of the impact to travel back to you. Assume the speed of sound is 1100 feet per second. 
Note: After  seconds the rock has reached a depth of  feet where

Set up and solve a quadratic equation.

anonymous · Answer

There was another one... but it was 4 seconds. I got the answer, which is 229.95 ft.

But as for this one, i couldn't get it anymore.. it keep saying my answer i input is incorrect. :(

anonymous · Answer

$$d=16t ^{2}$$