A 21.6-kilometer-long road was originally planned to be completed in 45 days, but it was actually built an extra 0.6 kilometers per day. How many days can it actually be completed?
修一条长21.6千米的路，原计划45天修完，实际每天多修0.6千米，实际几天可以修完？
<gadget id="calculator">21.6 / 45</gadget>
<output>0.48</output>

<gadget id="calculator">0.48 + 0.6</gadget>
<output>1.08</output>

<gadget id="calculator">21.6 / 1.08</gadget>
<output>20</output>

<result>20</result>