There are 41 students in a class, and each of them has 10 to 50 yuan in their hands. They go to the bookstore to buy books. They know that a paperback book is 3 yuan a piece, and a hardcover book is 4 yuan a piece. They are required to use up all the money in their hands and buy as many books as possible. How many hardcover books did you have?
某班有41名同学，每人手中有10元到50元钱各不相同．他们到书店买书，已知简装书3元一本，精装书4元一本，要求每人都要把自己手中的钱全部用完，并且尽可能多买几本书，那么最后全班一共买了多少本精装书？
<gadget id="calculator">14 * 2</gadget>
<output>28</output>

<gadget id="calculator">14 + 28</gadget>
<output>42</output>

<result>42</result>