((x)/20)=(15/8).
((x)/20)=(15/8)．
<gadget id="calculator">15 / 8</gadget>
<output>15/8 = around 1.875</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(15/8) / (1/20)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>