Xiao Hui is 6 years old this year, and her father is 5 times her age this year. How many years later, her father will be 3 times Xiao Hui's age.
小惠今年6岁，爸爸今年年龄是她的5倍，多少年后，爸爸年龄是小惠的3倍．
<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<gadget id="calculator">30 - 18</gadget>
<output>12</output>

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

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<result>6</result>