A technical book, Lu Jie plans to read 20 pages a day, and finish it in 6 days. As a result, he finished reading it in 4 days. How many pages does Lu Jie actually read every day?
一本科技书，吕洁计划每天看20页，6天看完．结果他4天就看完了，吕洁实际每天看了多少页？
<gadget id="calculator">20 * 6</gadget>
<output>120</output>

<gadget id="calculator">120 / 4</gadget>
<output>30</output>

<result>30</result>