Peters Bicycle company assembles M$-5$ trail bikes that sell for $$700$ per bike. The materials and parts for each bike cost $239$ $$/$bike$.$ The overhead cost for operating his shop is $$5,630.$ per week. a$)$ What is the contribution margin for each bike sold? b$)$ What is the break even point in weekly sales? c$)$ How many bikes does he have to sell in a week to make $$2,000.$ profit?