The engineering team repairs a section of expressway with an average of 16.5 kilometers per month. After 18 months of repairs, it is still 18.5 kilometers away from the midpoint. How many kilometers is the total length of this expressway?
工程队保修一段高速公路，平均每月修16.5千米，修了18个月后，离中点还有18.5千米，这段高速公路全长多少千米？
<gadget id="calculator">16.5 * 18</gadget>
<output>297</output>

<gadget id="calculator">297 + 18.5</gadget>
<output>315.5</output>

<result>315.5</result>