Class 1 of the fourth grade scored an average of 85.13 points in the statistical math test. After review, it was found that Xiaohua's score of 87 was written as 78 points by mistake. After recalculation, the average score of Class 1 of Grade 4 is 85.31 points. How many students are there in this class?
四年级1班在统计数学考试成绩，平均分为85.13分，经复查发现将小花的成绩87分误写成了78分．重新计算后，四年级1班平均成绩是85.31分．请问这个班有多少名学生？
<gadget id="calculator">87 - 78</gadget>
<output>9</output>

<gadget id="calculator">85.31 - 85.13</gadget>
<output>0.18</output>

<gadget id="calculator">9 / 0.18</gadget>
<output>50</output>

<result>50</result>