Xiao Ming wants to read a book. He originally planned to read 10 pages a day and finish it in 30 days. Now he decides to read 5 more pages a day. How many days can he finish it? (Solve with ratio)
小明要看一本书，原计划每天看10页，30天可以看完，现在决定每天多看5页，几天可以看完？(用比例解)
<gadget id="calculator">10 * 30</gadget>
<output>300</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">300 / 15</gadget>
<output>20</output>

<result>20</result>