The farm needs to plow a piece of land, and it is planned to plow 12 hectares every day, which will be completed in 5 days. 15 hectares are actually plowed every day, how many days are actually plowed? (Solve with ratio)
农场要耕一块地，计划每天耕12公顷，5天正好耕完．实际每天耕15公顷，实际多少天耕完？(用比例解)
<gadget id="calculator">12 * 5</gadget>
<output>60</output>

<gadget id="calculator">60 / 15</gadget>
<output>4</output>

<result>4</result>