A batch of A4 paper is used to print a 140-page book, which is just enough to print 15 volumes. How many volumes of the same book can be printed if such paper is tripled.
一批A4纸，用来印刷140页的书，刚好够印15册．如果这样的纸张增加到原来的3倍，能够印刷同样的书多少册．
<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<result>45</result>