40% of the number A is equal to (8/9) of the number B, the number A is 20, what is the number B.
甲数的40%等于乙数的(8/9)，甲数是20，乙数是多少．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">(2/5) / (8/9)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">20 * (9/20)</gadget>
<output>9</output>

<result>9</result>