Determine the best insulation thickness, using simple payback period analysis, to insulate a hot water storage tank with a capacity of 500 gallons. The cost of fiberglass insulation is as follows: $2.60/ft2 for 1 in., $2.95/ft2 for 2 in., and $3.60/ft2 for 3 in. fiberglass insulation. The average ambient temperature surrounding the tank is 65°F. Assume appropriate dimensions for the 500-gallon tank.