# Thread: Solving word problems using derivatives

1. ## Re: Solving word problems using derivatives

Here is a plot of the revenue function for problem 1:

2. ## Re: Solving word problems using derivatives

Yes, thank you. I managed to finish that one. I got 250 passengers. Which seems much more reasonable than my first answer of 15000...

3. ## Re: Solving word problems using derivatives

Okay, I understand that I need to substitute x^2 in for y, but in what? In the distance formula?

4. ## Re: Solving word problems using derivatives

How did you get 250 passengers? What is the revenue function at x = 250?

5. ## Re: Solving word problems using derivatives

The problem said to find the number of passengers, not the greatest revenue.

6. ## Re: Solving word problems using derivatives

Originally Posted by ktkeiper
The problem said to find the number of passengers, not the greatest revenue.
A chartering company will provide a plane for a fare of \$300 per person for 100 or fewer passengers (but more than 60 passengers.) For each passenger over 100, the fare is decreased \$2 per person for everyone. What number of passengers would provide the greatest revenue?
fyi, at x = 250 passengers, revenue = 0

7. ## Re: Solving word problems using derivatives

What formula did you use? Because with my formula, the revenue came out to \$62500

8. ## Re: Solving word problems using derivatives

Originally Posted by ktkeiper
What formula did you use? Because with my formula, the revenue came out to \$62500
for $x > 100$ ...

$R = x(500-2x)$

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