Master Zhang in the school cafeteria went to the supermarket to buy hairtail. He bought 15 kilograms of hairtail at a discounted price and could buy 5 kilograms more. The discount for hairtail was 16.8 yuan per kilogram.
学校食堂的张师傅去超市买带鱼，原来买15千克的钱按优惠价可以多买5千克，带鱼打折16.8元/千克，优惠前每千克带鱼的售价是多少元？
<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<gadget id="calculator">20 / 15</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">16.8 * (4/3)</gadget>
<output>22.4</output>

<result>22.4</result>