Now, the age of the father is 5 times the sum of the ages of the two sons; after 6 years, it will shrink to 2 times. Three years from now, the eldest son will be twice as old as the youngest son. Find the father's current age.
现在，父亲的年龄是两个儿子年龄总和的5倍；6年后，缩成2倍．由现在起，3年后，长子的年龄为幼子的2倍．求父亲现在的年龄．
<gadget id="calculator">2 * 12</gadget>
<output>24</output>

<gadget id="calculator">24 - 6</gadget>
<output>18</output>

<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">18 / 3</gadget>
<output>6</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<result>30</result>