6. A forest fire is burning down a narrow valley three miles wide at a speed of 40 feet per minute. The fire can be contained by cutting a firebreak through the forest across the valley. It takes 30 seconds for one person to clear one foot of the firebreak. The value of lost timber is $4,000 per square mile. Each person hired is paid $18 per hour, and it costs $50 to transport and supply each person with the appropriate equipment.

a. Develop a model for determining how many people should be sent to contain the fire and for determining the best location for the firebreak (draw a picture first!).

b. Implement your model on a spreadsheet and find the optimal solution using Solver .