Johnson Engineering produces two types of drill bits for the mining industry: a 3/4" model and a 1" model. The manufacturing process takes place in three departments. Tip fabrication makes tungsgten carbide tips out of powdered wolfram. The forging department slots the alloy steel rod and heat treats it for strength. Finally, the assembly department attaches the tips to the rods in a high-temperature brazing process. Information about production during the month of July is provided below.

			3/4 Inch	1 Inch	Total
Production volume (# untis)			250	400
Selling Price			$28.50	$38.50
Direct Material			$8.25	$11.10
Direct Labor			$5.30	$9.65
Manufacturing OH*			$8.40	$11.00
Gross profit

* This included utilities, manufacturing management salaries, quality control, production planning, manufacturing engineering, accounting, property taxes, and other indirect support costs that could not be traced to the individual products. It was generally agreed that these costs did not vary over the volume ranges anticipated in the near future.

What is the weighted average contribution margin?

What is break-even sales volume?			# 3/4" bits	# 1" bits