Solve the equation: (2/3)x+(1/6)x=15, x=how much.
解方程：(2/3)x+(1/6)x=15，x=多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/3) + (1/6)</gadget>
<output>5/6 = around 0.833333</output>

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

<result>18</result>