Thread: Solving rational inequalties application problem help

Here's the problem:

An economist for a sporting goods company estimates the revenue and cost functions for the production of a new snowboard. These functions are and , respectively, where x is the number of snowboards produced, in thousands. The average profit is defined by the function AP(x) = P(x) / x , where P(x) is the profit function. Determine the production levels that make AP(x) > 0

What i did is :




Is this the right inequality to solve the problem?

Won't profit be ?

Originally Posted by pickslides

Won't profit be ?

Yeh, so i factored out the negative and put the equation into the quadratic formula to find the x's which are 6.74 and -0.74. So -0.74 < x < 6.74

but the answer according to the book is 1 < x < 5