A painter needed 6 pints of grey paint, so he mixed 4 pints of black paint with 2 pints of white paint. This turned out to be too dark a grey and he realised that what he really needs is a mixture that has 4 pints of white with 2 of black.
The painter understands that he will have to throw away some of the paint, but wants to get the correct amount of the right mixture with as little waste as possible. How should he do it?
If he were to discard half of the paint he has mixed, he will have 3 pints of a 2:1 mixture of black to white. This is the equivalent of 2 pints of black and one of white. If he now adds three pints of white, he will have the correct mixture (two pints of black and four of white) The waste is three pints
The other "easy" alternatives would have been to add six pints of white to get the color right and Start over fresh. Either would waste six pints
Any "complicated" scheme of adding some paint, discarding some paint, adding more paint, etc. will waste some amount between the three and the six, so the three is the smallest amount that you can manage
A

Posted by TomM
on 20020629 13:34:31 