Use a batch of paper to bind an exercise book. If 120 books have been bound, the remaining paper is 40% of these papers; if 185 books have been bound, there are 1350 papers left. How many sheets are there in total?
用一批纸装订一种练习本．如果已装订120本，剩下的纸是这些纸的40%；如果装订了185本，则还剩下1350张纸．这批纸一共有多少张？
<gadget id="calculator">90 * 200</gadget>
<output>18_000</output>

<result>18_000</result>