Carlyle Lighting Products produces two different types of lamps: a floor lamp and a desk lamp.

Floor lamps sell for $30 and desk lamps sell for $20.

The projected income statement for the upcoming year follows:

Sales $600,000

Less: Variable costs 400,000

Contribution margin 200,000

Less: Fixed costs 150,000

Operating income $50,000

The owner of Carlyles estimates that 60 percent of the sales revenues will be produced by floor lamps and the remaining 40 percent by desk lamps.

Floor lamps are also responsible for 60 percent of the variable expenses. Of the fixed expenses, one-third are common to both products, and one-half are directly traceable to the floor lamp product line.

Required: By what percentage will profits increase with this change in sales volume? What is the theory behind the operating leverage concept?