It's just a quadradic...Need Help!

[mrpickle]

Hey Guys, been awhile since I've been back here. Simba 0.97! :D

Anyways, I have a problem that I need help with. The question is about finding fuel efficiency (distance / fuel used) for a vehicle. So here's the given equation.
1. f(s) = (s - 10)^2 + 9900
f(s) represents the fuel consumption rate in (milliliters per hour)
s represents the speed of the vehicle in (kilometers per hour)

The answer needed is in (distance/fuel used), and must be the most efficient at that.

Well. Help would be very much appreciated!
Thanks,

~mrpickle

[bolshak25]

okay i got it distance = speed * time
and fuel used = rate * time
so st/f(s)t simplifies to s/f(s)
so use s as x and graph it.
x/((x-10)^2+9900)
then find maximum which is x = 100
plug into the consumption rate and get 18000
then put into distance over fuel used
100t/18000t
simplify to 1km/180ml

[mrpickle]

THAT MAKES SENSE! lol. I couldn't figure it out in 1h... and then gave up xD.
Thanks again :D