Dongxiong reads a book, 15 pages a day, which can be finished in 18 days. If you read 3 more pages a day, how many days can you finish reading? (Solve with ratio)
东雄读一本书，每天读15页，18天可以读完．如果每天多读3页，几天可以读完？(用比例解)
<gadget id="calculator">15 * 18</gadget>
<output>270</output>

<gadget id="calculator">3 + 15</gadget>
<output>18</output>

<gadget id="calculator">270 / 18</gadget>
<output>15</output>

<result>15</result>