1) Johnson's profit is
... net profit = selling price - costs = $155 - 35.00 - 39.17 - 36.43 = $44.40
His net earnings per hour are then
... earnings/hours = $44.40 / (4.5 h) = $9.87/h
2) net profit = selling price - overhead - cost
... net profit = selling price - 0.45 × selling price - cost . . . . substitute for overhead
... net profit = 0.55 × selling price - cost
Given that overhead = 0.45 × selling price, we can find selling price by dividing by 0.45:
... selling price = overhead/0.45
Using this in the profit equation, we have
... net profit = 0.55×(overhead/0.45) - cost
... = (0.55/0.45) × $65.34 - 49.32 . . . . . . substitute given numbers
... net profit = $30.54
