Mary saved exactly 60 percent of the total allowance she received in the last two weeks,and spent

问题描述:

Mary saved exactly 60 percent of the total allowance she received in the last two weeks,and spent
the rest.If she received $20 for allowance each week and spent $12 of her first week's allowance,which of the following must be true?

玛丽节省下了之前两周收到的津贴总额的60%,花掉了其余的部分.如果她每周得到的津贴为20美元,而她花去了上周津贴中的12美元,那么以下哪项必定为真?