(1/5) of a number is 15 less than its (3/4), what is this number?
一个数的(1/5)比它的(3/4)少15，这个数是多少？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

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

<gadget id="calculator">(3/4) - (1/5)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">15 / (11/20)</gadget>
<output>300/11 = around 27.272727</output>

<result>300/11 = around 27.272727</result>