It takes A 15 minutes to make a part, and B is faster (1/5) than A, how many minutes does B need?
甲做一个零件要15分钟，乙比甲速度快(1/5)，乙要多少分钟．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">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">(1/15) * (6/5)</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">1 / (2/25)</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>