[求助]PREP 1有道数学题看不懂题目,请大虾帮忙翻译下阿~~~

Before being simplified, the instructions for computing income tax in Country R were to add 2 percent of one's annual income to average (arithmetic mean) of 100 unitsof Country R's currency and 1 percent of one's annual income.Which of the following represents the simplified formula for computing the income tax , in Country R's currency, for a person in that country whose annual income is I?

以上黄色部分不知是什么意思，请大虾指点，感激不尽！

年收入的2%+100加上年收入1%的平均=I*2%+(I*1%+100)/2