Could you pleawe help me answer all of this ??

Problem 3 (30%) The fixed cost for a steam line per meter of pipe is $1500X + $150 per year. The cost of loss of heat from de pipe per meter is $15/x0.5 per year. Xrepresents the thickness of the insulation in meters, X is a continuous design variable. a. What is the optimum thickness of the insulation? b. How do you know that your results of (a) minimizes total cost per year? Questions (10%) Select fixed or variable costs of driving your own car from the items in the below table. Fixed cost $ Variable cost $ Cost Depreciation Licenses Fuel Tolls Maintenance insurance parking Common car loan monthly payment