There is a batch of homework. Mr. Wang originally planned to correct 6 books per hour. After grading for 2 hours, he decided to correct 8 books per hour. As a result, he finished correcting 3 hours ahead of schedule. How many books are there in this batch of homework?
有一批作业，王老师原计划每小时批改6本，批改了2小时后，他决定每小时批改8本，结果提前3小时批改完，那么这批作业有多少本？
<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<gadget id="calculator">24 + 4</gadget>
<output>28</output>

<gadget id="calculator">8 - 6</gadget>
<output>2</output>

<gadget id="calculator">28 / 2</gadget>
<output>14</output>

<gadget id="calculator">6 * 14</gadget>
<output>84</output>

<result>84</result>