A crude oil pipeline is to be built to carry oil at a rate of 1 million $\mathrm{bbl} / \mathrm{day}(1 \mathrm{bbl}=42 \mathrm{gal})$. If the pipe cost $\$ 12 / \mathrm{ft}$ of length per inch of diameter, power to run the pumps costs $\$ 0.07 / \mathrm{kWh}$, and the economic lifetime of the pipeline is 30 years, what is the most economical diameter for this pipeline? What total horsepower would be required of the pumps if the line is 800 miles long, assuming $100 %$ efficient pumps? (Oil: viscosity $=35 \mathrm{cP}$, density $=0.85 \mathrm{~g} / \mathrm{cm}^{3}$ )?