Taking the same distance, B takes 1/5 more time than A, and B's speed is A's.
走相同的路程，乙用的时间比甲多(1/5)，乙的速度是甲的多少．
<gadget id="calculator">1 / 1</gadget>
<output>1</output>

<gadget id="calculator">1 / 1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">1 / 1 / (6/5) / 1 / 1</gadget>
<output>5/6 = around 0.833333</output>

<result>5/6 = around 0.833333</result>