Northern Construction and Engineering plans on opening an office in Duluth. Over the next 25 years, the office is expected to have a positive cash flow of $250,000 per year. In year 25; the office can be sold for $1M. At an interest rate of 12%, what is the equivalent present worth?

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.