The sum of the ages of A, B, and C is 27 years; the sum of the ages of B, C, and D is 33 years, and the sum of the ages of A and D is twice the sum of the ages of B and C. The sum of the ages of the four of them is How old are you?
甲、乙、丙三人的年龄和是27岁；乙、丙、丁三人的年龄和是33岁，甲、丁年龄和是乙、丙年龄和的2倍，他们四人的年龄和是多少岁？
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">30 + 25</gadget>
<output>55</output>

<result>55</result>