You drop a rock into a deep well. You can't see the rock's impact at the bottom, but you hear it after 4 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 $t$ seconds the rock has reached a depth of $d$ feet where $$d = 16t^2.$$ Set up and solve a quadratic equation.