Math CentralQuandaries & Queries


Question from nick, a student:

hello, this is my first time asking for help from this website in which by the way, i think is great for everyone. My question is as follows... the relationship between the selling price of a sleeping bag, s dollars, and the revenue at that selling price, r(s) dollars is represented by the function: r(s)= -10s^2+1500s
evaluate, interpret, and compare: a) r(29.95)

We have two responses for you.

Hi Nick.

Glad you found Math Central.

r(29.95) is the revenue earned by setting the selling price to be $29.95. If you replace s with 29.95 in the function, you get this:

-10(29.95)2 + 1500(29.95) = -8970.03 + 44925.00 = $35954.97

So if the manufacturer sets the price at $29.95 per sleeping bag, she can expect a revenue of $35 954.97.

Your question said "evaluate, interpret and compare" but there was only this one expression: r(29.95). Were you given others (like r(19.95) or r(24.95)?) to compare it with? If so, evaluate those values and determine what price of those given will give the most revenue.

Hope this helps,


Hi Nick,

I also am confused by the word compare. To help with interprret however I would draw a graph of r(s) = -10 s2 + 1500 s.

Notice that r(0) = 0. Is there another value of s so that r(s) = 0? Can r(s) be negative for some values of s? Does the revenue continue to increase as the price s increases? Can r(s) be negative for some values of s?


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