A canal was built in Xinhe Township. On the first day, 44.5 meters were built, which was 2.5 meters more than twice the amount built on the second day. How many meters were built on the second day?
新河乡修了一条水渠，第一天修了44.5米，比第二天修的2倍多2.5米，第二天修了多少米？
<gadget id="calculator">44.5 - 2.5</gadget>
<output>42</output>

<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<result>21</result>