The two-way construction of the tunnel across the river, team A digs 4.2 meters every day, team B digs 0.4 meters less than team A every day, the total length of the tunnel is 205 meters. After the two teams worked at the same time for 20 days, for some reason, Team A worked for two more days. How many meters is the undug tunnel?
过江隧道双向施工，甲队每天挖进4.2米，乙队每天比甲队少挖0.4米，隧道总长是205米．两队同时做了20天后，因故，甲队多做了两天，未挖通的隧道有多少米．
<gadget id="calculator">4.2 - 0.4</gadget>
<output>3.8</output>

<gadget id="calculator">4.2 + 3.8</gadget>
<output>8</output>

<gadget id="calculator">8 * 20</gadget>
<output>160</output>

<gadget id="calculator">4.2 * 2</gadget>
<output>8.4</output>

<gadget id="calculator">160 + 8.4</gadget>
<output>168.4</output>

<gadget id="calculator">205 - 168.4</gadget>
<output>36.6</output>

<result>36.6</result>