Commercial gross profit refers to the difference between the selling price minus the purchase price (cost). The gross profit per item before the price reduction of a certain commodity is 15% of the selling price, and 100 units are sold every day; after the price reduction (the purchase price remains unchanged), 150 more units are sold per day than before, and the total gross profit per day after the price reduction is the gross profit before the price reduction (5/3) of the total amount. Ask how much the price has dropped? (Assume that the buying price is a yuan, and the selling price before the price reduction is b).
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(5/3)．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)．
<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">1 - (19/20)</gadget>
<output>1/20 = around 0.05</output>

<result>1/20 = around 0.05</result>