Help please (1 Viewer)

[rawker]

the cost of running a car at an average speed of v km/h is given by c= 150 + (v^2 / 80) cents/km. find the average speed, to the nearest km/h, at which the cost of a 500 km trip is a minimum


i derived that, so that i had dc/dv = v/160 , which then i made = 0
v=0....
d^2c/dv^2 = 1/160 > 0 (min)



then what?

 

[yodajones2000]

I am too lazy to figure it out now. But this is one of those questions with more than one possible answer.

 

[SoulSearcher]

The same exact question is answered in this thread.
http://community.boredofstudies.org...n-someone-explain-how-do-question-please.html