Liangliang is reading a popular science book. He plans to read 20 pages a day and finish it in 28 days. Due to his busy study, he actually only reads 16 pages a day. At this speed, how many days did it actually take to finish reading this book?
亮亮正在读一本科普书，计划每天读20页，28天读完，由于学习比较忙，实际每天只读16页，按这样的速度，读完这本书实际用了多少天？
<gadget id="calculator">28 / 16</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">20 * (7/4)</gadget>
<output>35</output>

<result>35</result>