For a truck, its fuel consumption in is given by
, where is the speed in . Find the speed that gives the best distance to fuel ratio
No calculus is to be used to solve this question
Any pointers? Was thinking of trying , but didn't know how to find the minimum without calculus
Are you sure? Talked to a friend and he said the answer was 100. He didn't give reasons, just hints.
Checking at , we have , so that is for every traveled in an hour, of fuel is consumed, giving us a consumption rate of
But at , we have , that is for every traveled in an hour, of fuel is consumed, giving us a consumption rate of
Is there something wrong with this reasoning?
No, there isn't. My method is incorrect. I had found the speed for which the fuel consumption is minimum, not the speed corresponding to the best distance to fuel ratio. As you have correctly stated we have to find the minimum of . But alas I still didn't get an idea to tackle this problem.