PLEASE HELP ME I WILL PAY YOU - DROP PAYMENT METHOD
An island is 3.5 miles from the nearest point on a straight shoreline; that point is 10 miles from a power station also sitting along the shoreline. A utility company plans to lay the electrical cable underwater from the island to the shore at some point, and then underground along the shore line to the power station. Assuming that it costs $2400/mile to lay underwater cable and $1200/mile to lay underground cable, at what point should the underwater cable meet the shore in order to minimize the cost of the entire project?
