Three types of drills can be used for drilling wells: 1) High speed stainless steel, 2) Gold Oxide, 3) Titanium Nitrite. The costs that would generate each one are indicated below: Stainless Steel Gold. Oxide Titanium Nitrite

Initial Cost (USD) 3,500 6,500 7,000

Monthly Operation Cost (USD/MONTH) 2,000 1,500 1,200

Useful Life (months) 3 6 6 With an annual interest rate of 12%, compounded monthly. Select the type of hole that should be used, based on the Future Value analysis.