The Grade 5 office bought a pack of white paper. It was planned to use 20 sheets per day, and it lasted for 28 days. The actual use was 7 days longer than the plan. How many sheets of this pack of paper actually used per day?
5年级办公室买进一包白纸，计划每天用20张，可以用28天，实际比计划多用了7天，这包纸实际每天用多少张？
<gadget id="calculator">20 * 28</gadget>
<output>560</output>

<gadget id="calculator">28 + 7</gadget>
<output>35</output>

<gadget id="calculator">560 / 35</gadget>
<output>16</output>

<result>16</result>