Stan Fawcett's company is considering producing a gear assembly that it now purchases from Salt Lake Supply, Inc. Salt Lake Supply charges $4 per unit with a minimum order of 3000 units. Stan estimates that it will cost $15000 to set up the process and then $1.82 per unit for labour and materials. a- draw a graph illustrating the crossover (or difference) points. b- Determine the number of units where either choice has the same cost.