A batch of paper can just bind a whole number of exercise books. If 120 books have been bound, the remaining paper is 40% of this batch of paper; if 185 books are bound, there are still 1350 sheets of paper left. How many pieces of paper are there in total?
用一批纸恰好能装订一种练习本整数本，如果已装订120本，剩下的纸是这批纸的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>