The sailfish is the champion swimmer in the ocean, it can swim 270 kilometers in 3 hours; the dolphin is also an expert swimmer, it can swim 180 kilometers in 3 hours, how much more kilometers can the sailfish swim on average than the dolphin per hour?
旗鱼是海洋中的游泳冠军，它3小时能游270千米；海豚也是游泳能手，它3小时能游180千米，旗鱼平均每小时比海豚多游多少千米？
<gadget id="calculator">270 / 3</gadget>
<output>90</output>

<gadget id="calculator">180 / 3</gadget>
<output>60</output>

<gadget id="calculator">90 - 60</gadget>
<output>30</output>

<result>30</result>