Some coal was brought in from the cafeteria. It is planned to burn 0.9 tons per day, which can be burned for 15 days, but actually burns 0.5 tons per day, how many days can it actually be burned?
食堂运来一些煤，计划每天烧0.9吨，可以烧15天，实际每一天烧0.5吨，实际可以烧多少天？
<gadget id="calculator">15 / 0.5</gadget>
<output>30</output>

<gadget id="calculator">0.9 * 30</gadget>
<output>27</output>

<result>27</result>