A batch of coal was brought in from the cafeteria, and it is planned to burn 105 kilograms per day, which can be burned for 30 days. After improving the stove, how many days can you burn 15 kg less per day?
食堂运来一批煤，计划每天烧105千克，可以烧30天．改进炉灶后，每天少烧15千克，可以烧多少天？
<gadget id="calculator">105 * 30</gadget>
<output>3_150</output>

<gadget id="calculator">105 - 15</gadget>
<output>90</output>

<gadget id="calculator">3_150 / 90</gadget>
<output>35</output>

<result>35</result>