Xiao Ming reads a book. If you read 25 pages a day, you can finish it in 12 days; if you read 30 pages a day, how many days can you finish it? (Solution by ratio).
小明看一本书．若每天看25页，12天看完；若每天看30页，几天可以看完？(用比例解)．
<gadget id="calculator">25 * 12</gadget>
<output>300</output>

<gadget id="calculator">300 / 30</gadget>
<output>10</output>

<result>10</result>