Math Is Fun Forum

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 160

Transporting fuel

A city has 13,500 litres of fuel in excess to be sent to another city in need at a distance of 450 miles.
The capacity of the available transport tank is 4500 litres and it consumes 10 litres/mile.
It is possible to use fuel reservoirs at many locations on the road as necessary.

The question is:
What is the maximum quantity of fuel that could be delivered at the second city?

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 160

Re: Transporting fuel

I heard of this problem in early 80’s from a person returning from France. He told me that it was a question in a context TV show (French) that couldn’t get an answer. After about 40 years, I am not sure what its original numbers were but I still remember how I solved it. Its few equations have each one variable (unknown) of the first degree.

For instance, when I was a student and before starting a math exam, I noticed a colleague in my classroom trying, in vain, to solve an exercise that was expected to be given in the exam. I thought that helping him is a good thing. So I reminded him the basic hint by which the exercise in question could be solved rather easily. He looked at me and said: “Who asked you for help? I bet you are happy now for proving you are smarter than I”. So I apologized, but since then I fully understood the famous saying “Ask and you will be given” which also means “Give if you are asked... otherwise don’t blame the other side for any unexpected reaction”

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 160

Re: Transporting fuel

The answer is:
The maximum quantity of fuel that could be delivered at the second city is 2400 litres.