A man runs his car out of gas thereby completely emptying his 16 gallon tank. He only has a 3, a 6, and a 11 gallon container (and fortunately a wagon to carry the containers in) in his trunk. He has nothing else in which he can carry gas. He walks a few miles to a gas station, and as luck would have it the gauge on the pump is broken so he can not use that to measure the fuel. He is in a pretty remote area with only one gas station for miles. Gas costs $3.09^{9}, and he only has a $50. Using only the containers provided, and only walking once to and from the gas station, how can he get exactly 16 gallons of gas into his car?
First, construct a balance where the two smaller cans (empty) balance out with the largest one (empty), thus establishing the tare. Next, fill the 11gal tank. From it, fill the 6gal tank. Then fill the 3gal tank and empty it into the 11gal tank. This leaves 8 gal in the 11gal tank and 6 gal in the 6gal tank. Now place the tanks on the balance. Begin filling the 3gal tank until it is balanced. It should take exactly two gallons to do this which yields 8 gallons on each side of the balance. Thus, 16 gallons.
Edited on September 24, 2007, 12:31 am

Posted by hoodat
on 20070924 00:29:44 