Red person is given a hundred dollars and can offer a split to blue. Let's say red wants to keep 70, and offers blue 30. So he offers a 70-30 split with blue.
小红人可以得到100美元，并且可以分一些给小蓝人 假设小红人想留下70美元， 给小蓝人30, 也就是七三分。