Question

The following function shows the relationship between the selling price (s), and profit P(s), in dollars, for a company:

P(s) = -20s^2 + 1,400s - 12,000

Which statement best describes the intervals where the company's profit increases, decreases, or records a maximum?

It is least when the selling price is $30.

It is greatest when the selling price is $30.

It decreases when the selling price increases beyond $35.

It increases when the selling price increases beyond $35.

Answer 1

@agent0smith

Answer 2

Find the derivative of P(s) and the critical point to get your answer.

Answer 3

do you mean the vertex?

Answer 4

Yeah, in this case the critical point is the vertex !

Answer 5

I know the vertex is 35 but how do I know if it is increasing or decreasing

Answer 6

i think c is correct

Answer 7

You get that from the sign of 'a' in ax^2 + bx + c
Here -20 is negative so the parabola will be like this

Answer 8

Great! Thanks so much!