求助，在线等，。急！！！

第四小题实在太难了。看不懂。前2题会做。，第3题勉强看懂，。第四题完全看不懂，不知道该怎么做，求老师解答，。在线等，。急！！！

hospital supply, inc., produced hydraulic hoists that were used by hospitals to move bedridden patients. the costs of manufacturing and marketing hydraulic hoists at the company’s norm volume of 3,000 units per month are shown below:

unit manufacturing costs:
variable materials           550
variable labor           825
variable overhead           420
fixed overhead           660
total unit manufacturing costs  2,455
unit marketing costs:
variable                            275
fixed                            770
total unit marketing costs  1,045
total unit costs                  3,500

questions:
the following questions refer only to the given data. unless otherwise stated, assume there is no connection between the situations described in the questions; treat each independently. unless otherwise stated, assume a regular selling price of $4,350 per unit. ignore income taxes and other costs not mentioned above or in a question itself.

1。what is the break-even volume in units? in sales dollars?

2。market research estimates that monthly volume could increase to 3,500 units if the price were cut form $4,350 to $3,850 per unit. would you recommend that this action be taken? what would be the impact on monthly sales, costs, and income?

3。an inventory of 200 units of an obsolete model of the hoist remains in the stockroom. these must be sold through regular channels at reduced prices or the inventory will soon be valueless. what is the minimum price that would be acceptable in selling these units?

4。a proposal is received from an outside contractor who will make 1,000 hydraulic hoist units per month and ship them directly to hospital supply’s customers as orders are received from hospital supply’s sales force. hospital supply’s variable marketing costs would be cut by 20 percent (to $220 per unit) for these 1,000 units produced by the contractor. the idle facilities would be used to produce 800 modified hydraulic hoists per month for use in hospital operating rooms. these modified hoists could be sold for $4,950 each, while the variable manufacturing costs would be $3,025 per unit and variable marketing costs would be $550 per unit. fixed marketing and manufacturing costs would be unchanged whether the original 3,000 regular hoists were manufactured or the mix of 2,000 regular hoists plus 800 modified hoists was produced. what is the maximum purchase price per unit that hospital supply should be willing to pay the outside contractor? should the proposal be accepted for a price of $2,475 per unit to the contractor?