Two people repaired a 864-meter-long canal, and a total of 540 meters was built in the first 15 days. How many days will it take to complete the repair at this speed?
2人修一条长864米的水渠，前15天共修540米，照这样的速度还要几天才能修完？
<gadget id="calculator">864 - 540</gadget>
<output>324</output>

<gadget id="calculator">540 / 15</gadget>
<output>36</output>

<gadget id="calculator">324 / 36</gadget>
<output>9</output>

<result>9</result>