Course:MATH110/Archive/2010-2011/003/Notes/Optimization/Problem 7

Question

You're driving to work when you realize that you forgot to turn off the tap. Knowing that the dripping faucet will cost you 40 cents per hour; that you are 10 kilometres away from home; and that if you drive at a constant speed of $v$ kilometres per hour the cost in gas is $8+v/20$ cents per kilometres. At which constant speed must you go back home to turn off the tap and minimize your total loss?