The town of Dry Gulch needs more water from Pine Creek.

The town of Dry Gulch needs more water from Pine Creek. The town engineer has selected two plans for comparison: a gravity plan (divert water at a point 10 miles up Pine Creek and pipe it by gravity to the town) and a pumping plan (divert water at a point closer to town). The pumping plant would be built in two stages, with half-capacity installed initialy and the other half installed 10 years later.
The analysis will assume a 40-year life, 10% interest, and no salvage value. Use an annual cash flow analysis to find which plan is more economical.
Graph attached...