A number plus 2 times 5 is exactly equal to 3 times this number, what is this number?
一个数加上5的2倍正好等于这个数的3倍，这个数是多少．
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<result>5</result>