# Math Help - Trouble with a max/min problem when the function is unkown.

1. ## Trouble with a max/min problem when the function is unkown.

A bushwalker can walk at 5 km/h through clear land and 3km/h through bushland. If she has to get from point A to point B following a route indicated at right, find the value of x so that the route is covered in a minimum time. *The diagram for the question is attached, jpeg, it needs to be zoomed in on.* Thank you

2. Originally Posted by amcta
A bushwalker can walk at 5 km/h through clear land and 3km/h through bushland. If she has to get from point A to point B following a route indicated at right, find the value of x so that the route is covered in a minimum time. *The diagram for the question is attached, jpeg, it needs to be zoomed in on.* Thank you
time = distance/rate

$t = \frac{\sqrt{x^2+4}}{3} + \frac{3-x}{5}$

can you finish?