下面出的是湖南、河南人民出版社出版的一本中学初一年级暑假作业中的一个习题。 世界名题:一牧场长满青草,27头牛六星期可以吃完,或者23头牛九星期可以吃完,若是21头牛,要几星期可以吃完呢?(注意,牧场的草是不断生长的。)这类问题是英国物理学家牛顿提出来的,称为“牛顿吃草问题”。 The following is an exercise in the first grade summer homework of a middle school in Hunan and Henan People’s Publishing House. World title: A pasture is full of grass, 27 cows can finish in six weeks, or 23 cows can finish in nine weeks. If there are 21 cows, it can be finished in a few weeks? (Note that the pasture grass is constantly Growing up.) This type of problem was proposed by Newton, a British physicist, and was called “Newton Grazing”.