Two ships, A and B, sail from Suzhou to Hangzhou at the same time. After 4 hours, ship B lags behind ship A by 14 kilometers. Ship A travels 23.5 kilometers per hour, how many kilometers per hour does boat B travel?
甲、乙两艘轮船同时从苏州驶向杭州，4小时后乙船落后甲船14千米．甲船每小时行23.5千米，乙船每小时行多少千米？
<gadget id="calculator">14 / 4</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">23.5 - (7/2)</gadget>
<output>20</output>

<result>20</result>