Answer:
The mean of the total number of students is 85.5
Step-by-step explanation:
REcall that given n data points[tex]x_1, \dots, x_n[/tex], the mean is given by
[tex] \frac{\sum_{i=1}^n x_i}{n}[/tex].
Let us number the students of the 24 students' class from 1 to 24 and the let us number the students of the other class from 25 to 47.
The question is to find the following
[tex] \frac{\sum_{i=1}^{47} x_i}{47}[/tex]
REcall the following
[tex]\frac{\sum_{i=1}^{24}x_i}{24} =86[/tex]
[tex]\frac{\sum_{i=25}^{47}x_i}{23} =85[/tex]
Then, from this equations we can deduce that
[tex]\sum_{i=1}^{47}x_i = \sum_{i=1}^{24}x_i + \sum_{i=25}^{47}x_i = 86\cdot 24 + 85\cdot 23[/tex]
Therefore,
[tex] \frac{\sum_{i=1}^{47} x_i}{47}= \frac{86\cdot 24 + 85\cdot 23}{47}= 85.5[/tex]