Mike Lazenby, an industrial engineer at Energy Conservation Service, has found that the anticipated profitability of a newly developed water-heater temperature-control device can be measured by present worth with the formula
NPW = 4.028V(2X - $11) - 77,860
Where V is the number of units produced and sold and X is the sales price per unit. Mike also has found that the value of the parameter V could occur any-where over the range from 1,000 to 6,000 units and that of the parameter X anywhere between $20 and $45 per unit. Develop a sensitivity graph as a function of the number of units produced and the sales price per unit.