A, B, and C are doing math problems. It is known that A has done 7 more problems than B, and C has done 30 more problems than B. How much did the three of them do in total?
甲、乙、丙三人做数学题，已知甲比乙多做7题，丙做的是甲的2倍，比乙多做了30道．他们三人一共做了多少道？
<gadget id="calculator">30 - 7</gadget>
<output>23</output>

<gadget id="calculator">23 * 4</gadget>
<output>92</output>

<gadget id="calculator">92 - 7</gadget>
<output>85</output>

<result>85</result>