A map of the sea floor with SONAR

A ship sails in a straight line and sends a SONAR pulse every kilometre. You will make the program turn each echo time into a depth, find the deepest point, and find where a hidden hill is shallowest. Then it draws the sea floor.

The idea. The pulse goes down and back up, so the depth is $d = \dfrac{vt}{2}$, with $v = 1500\ \text{m/s}$ in sea water.

Your tasks.

1. Inside the loop, work out d, the depth below each point, in metres.
2. Find deepest, the greatest depth, in metres.
3. Find top_km, the kilometre mark where the sea is shallowest (the top of the hill).