Question: A power cable must be laid from a power plant to a new factory located across a shallow river. The river is 50 feet wide and the factory is 200 feet downstream and 100 feet from the bank. The cable cost $600 per foot to lay under water, $100 per foot to lay along the bank, and $200 per foot to lay from the bank to the factory. What path should be taken to minimize the cost and what is the minimum cost?