15 people build a canal, and each person builds 7.8 meters per day. How many meters can they build in September?
15个人修一条水渠，每人每天修7.8米，九月份一共能修多少米？
<gadget id="calculator">7.8 * 15 * 30</gadget>
<output>3_510</output>

<result>3_510</result>