Math
posted by Lucy X .
Hey, I posted this question before, but I really need some help.
Thanks...

A delivery business plans to serve three towns on a stretch of highway. For every trip they make to town A, which we'll place at position x=0, they expect to make two trips to town B (at position x=1) and 3 trips to town C (at position x=4). If they build their delivery centre at position x, then, their daily driving time should be proportional to d(x) = x + 2x  1 + 3x  4. The owners are thinking of building the center in town C, since it's the biggest but overhead costs would be lower in town B. Where should they build?

Well, I think I should sketch the function too, but I don't know how...

first, when you make a "trip", one goes there and comes back, so the distance is 2 times ..
On the last question, do the cost function for driving. You will see the cost difference for the initial position, first for x=0, then for x=3 
Well, I graphed d(x).
I'm not sure how I am supposed to use it to determine the best position...
Sorry, I don't understand how to do the cost function, since no cost information is given...