muspest supplies is currently evaluating the cost of manufacturing some of the components utilised in their products. currently the company expects to need 8,000 parts each month. a supplier of the part has been identified and the total cost of purchasing the parts on a monthly basis would be 36,000. in analysing the part costs, the direct labour and materials cost would be 21,000 and the variable overheads would be 5000. based only on relevant cost per unit what is the unit costs to purchase and unit costs to produce?