题目

If you feel sleepy every morning, don't blame yourself. Your work schedule could be to blame. A recent research shows that, for many of us, our work schedules do not agree with our natural body clocks—and experts are urging employers to take notice.  “When work schedules agree with people's natural sleep patterns, they produce higher quality and more creative work because they are more focused, less stressed and generally healthier. The opposite is also true—when employees are sleep deprived, they are more likely to make major mistakes and suffer from workplace injuries，” sa商业毛利指售价减去买入价（成本）后的差．某种商品降价前每件毛利是售出价的15%，每天售出100件；降价（买入价不变）后，每天比原来多销售150件，且降价后每天毛利总额是降价前毛利总额的53．问售价降了百分之几？（假设买入价为a元，降价前售出价为b）．