To build a road, it is planned to build 3.2km per day, and it will be completed in 45 days. In fact, an extra 0.4km will be repaired per day. How many days will it actually be completed?
修一条公路，计划每天修3.2km，45天修完，实际每天多修0.4km，实际多少天修完？
<gadget id="calculator">3.2 + 0.4</gadget>
<output>3.6</output>

<gadget id="calculator">45 / 3.6</gadget>
<output>12.5</output>

<gadget id="calculator">3.2 * 12.5</gadget>
<output>40</output>

<result>40</result>