最近本人刚刚开始看Osborne的《博弈入门》，但是开头就遇到了问题。第五页的一个小练习， 关于altruistic preference。各位论坛的童鞋肯定水平比我好太多，能不能帮我解答一下疑问呢？问题如下：
Person 1 cares about both her income and person 2's income. Precisely, the value she attaches to each unit of her own income is the same as the value she attaches to any two units of person 2's income. For example, she is indifferent between a situation in which her income is 1 and person2's is 0, and one in which her income is 0 and person 2's is 2. How do her preferences order the outcome (1,4), (2,1) and (3,0), where the first component in each case is her income and the second component is person 2's income? Give a payoff function consistent with these preferences.
这个问题前面说第一个人关心他本人跟第二个人的收益，并且他认为他本人一个单位的收益同第二个人两个单位的收益有同等价值。但是后面举的例子我就不太明白，他为什么对(1,0)跟(0,2)的组合评价相同呢？这里不明白，后面的问题我也没法回答。
自知水平很差，在此诚心求教，希望好心的童鞋指点，非常感谢！