A rock is dropped from rest into a well. The well is not really 16 seconds deep,

Question:

A rock is dropped from rest into a well. The well is not really 16 seconds deep, as in Figure P2.70.
(a) The sound of the splash is actually heard 2.40 s after the rock is released from rest. How far below the top of the well is the surface of the water? The speed of sound in air (at the ambient temperature) is 336 m/s.
(b) What If? If the travel time for the sound is neglected, what percentage error is introduced when the depth of the well is calculated?