MathProblem 14 Four pints of beer problem

A bartender has a \(3\) pint glass and a \(5\) pint glass. A customer walks in and orders \(4\) pints of beer. Without a measuring cup but with an unlimited supply of beer how does he get \(4\) pints in either glass?

Solution

用 \(3\) 和 \(5\) 的来得到 \(4\)。很经典的问题。

考虑到如何得到 \(4\): \(5-1=4\) 或者 \(3-1=2\). 当我们将 \(5\) 可以拆分为\(3+2\)：即将满瓶的 \(5\) 倒入 \(3\) 中，可以得到 \(2\); 将\(3\) 倒掉，将剩余的 \(2\) 倒入小瓶。此时小瓶剩余 \(1\)， 这时我们将大瓶倒满，再倒去 \(1ml\) 即可得到 \(4ml\).