英语翻译Alice's take-home pay last year was the same each month,

英语翻译
Alice's take-home pay last year was the same each month,and she saved the same fraction of her take-home pay each month.The total amount of money that she had saved at he end of the year was 3times the amont of that portion of her monthly take-home pay that she did not save.If all the money that she saved last year was from her take-home pay,what fraction of her take-home pay did she save each month?
A.1/2
B.1/3
C.1/4
D.1/5
正确答案是D
我觉得是文字的意思上有陷阱，但翻译不出来