Huanghua Town built a 2.1-kilometer-long embankment. In the first 15 days, an average of 0.086 kilometers was repaired per day. The rest will be completed within 9 days. How many kilometers are repaired on average per day?
黄花镇修一条长2.1千米的河堤，前15天平均每天修0.086千米，余下的要在9天内完成，平均每天修多少千米？
<gadget id="calculator">0.086 * 15</gadget>
<output>1.29</output>

<gadget id="calculator">2.1 - 1.29</gadget>
<output>0.81</output>

<gadget id="calculator">0.81 / 9</gadget>
<output>0.09</output>

<result>0.09</result>