The average of the two numbers of A and B is 9. The number A is (1/5) of the number B. What is the number of A
甲乙两数的平均数是9．甲数是乙数的(1/5)．则甲数是多少
<gadget id="calculator">9 * 2</gadget>
<output>18</output>

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

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">18 / (6/5)</gadget>
<output>15</output>

<gadget id="calculator">15 * (1/5)</gadget>
<output>3</output>

<result>3</result>