Xiao Wang's collection of books does not exceed 50 volumes, of which (1/7) are knowledge books, (1/3) are literary works, and (1/2) are mathematics textbooks, so how many books does Xiao Wang have in his collection.
小王的藏书还没有超过50册，其中(1/7)是知识读物，(1/3)是文学作品，(1/2)是数学教材，则小王已有藏书多少册．
<gadget id="calculator">2 * 3 * 7</gadget>
<output>42</output>

<result>42</result>