A truck gets 600/x miles per gallon (mpg) when driven at a constant speed of x mph, where 40 ≤ x ≤ 80?
A truck gets 600/x miles per gallon (mpg) when driven at a constant speed of x mph,
where 40 ≤ x ≤ 80.
If the price of fuel is $2.80/gal and the driver is paid $19/hr,
at what speed is it most economical for the trucker to drive?
(Round your answer to two decimal places.)
Update:answer in miles/hour
More Questions From This User See All
Answers & Comments
Verified answer
cost of fuel/mile = 2.8x/600 = 7x/1500
cost of driver = 19/x
total cost C = 7x/1500 + 19/x
C' =7/1500 -19/x^2, and C" = 38/x^3,iie positive for x > 0
setting C' to zero, 7/1500 = 19/x^2, x = 63.81 mph <-----