Question 252672
A class of 10 students has an average score of 95. 
Total marks = 10*95 = 950
Another class of 15 students has an average score of 80.
Total marks = 15*80 = 1200
Total number of students in both classes = 10+15 = 25
Total marks obtained by the students in both classes = 950+1200 = 2150
Weighted average of all the students = 2150/25
                                     = 86