Solution ratio: 18: x=(3/10):5.
解比例：18：x=(3/10)：5．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">5 / (3/10)</gadget>
<output>50/3 = around 16.666667</output>

<gadget id="calculator">18 * (50/3)</gadget>
<output>300</output>

<result>300</result>