1. Jan 14, 2012

nyr

Okay so I need help with 2 problems. One I did a bunch of work for but im not sure if my answers right, and the second I'm not sure how to start it.
The first problem:

A real estate office handles 50 apartment units. When the rent is $720 per month, all units are occupied. However, on average, for each$40 increase in rent, one unit becomes vacant. Each occupied unit requires an average of $48 per month for services and repairs. what rent should be charged to obtain the maximum profit. My work: I set up an equation R= (50-x)(720+40x)-48(50-x) R'=1328-80x critical number at x=16.6 50-16.6=33.4 R(16.6)/33.4=1336$1336 should be charged to obtain the maximum profit.

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The second problem:
When a wholesaler sold a certain product at $25 per unit, sales were 800 units per week. After a price increase of$5, the average number of units sold dropped to 775 per week. Assume that the demand function is linear and find the price that will maximize the total revenue.

I have no idea how to set up this problem