Blue whales can swim 60 kilometers per hour, slower than dolphins (1/7). How many miles can a dolphin swim per hour?
蓝鲸每小时可以游60千米，比海豚的速度还慢(1/7)．海豚每小时可以游多少千米？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">60 / (6/7)</gadget>
<output>70</output>

<result>70</result>