In a ratio, the product of two outer terms is the smallest composite number, one of which is (1/5), and what is the other inner term.
在一个比例中，两个外项积为最小合数，其中一个内项是(1/5)，另一个内项是多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / (1/5)</gadget>
<output>20</output>

<result>20</result>