The road repair team completed a road in 3 months, and 120 kilometers in the second and third months, 30 kilometers less than three times the repair in the first month. How long is this road in kilometers?
修路队3个月修完一条公路，第2、3两个月修了120千米，比第一个月修的3倍少30千米，这条公路长多少千米？
<gadget id="calculator">120 + 30</gadget>
<output>150</output>

<gadget id="calculator">150 / 3</gadget>
<output>50</output>

<gadget id="calculator">50 + 120</gadget>
<output>170</output>

<result>170</result>