Mighty Bright Window Cleaners monthly income statement at several levels of activity is as follows:

Windows washed		2,500		4,800		6,700
Sales revenue	$	3,800	$	7,296	$	10,184
Cost of goods sold		1,400		2,688		3,752
Gross profit		2,400		4,608		6,432
Operating expenses
Advertising expense		400		400		400
Salaries and wages expense		750		980		1,170
Insurance expense		200		200		200
Postage expense		450		864		1,206
Total operating expense		1,800		2,444		2,976
Operating income	$	600	$	2,164	$	3,456

(b) Prepare a contribution margin income statement based on a volume of 4,150 windows. (Round unit cost to 2 decimal places, e.g. 12.25 and all other answers to 0 decimal places, e.g. 45,000.) 4,150 windows Per Unit