The mean of marks secured by 45 students in division A of class X is 69, 65 students of division B is 65 and that of 50 students of division C is 63. Find the mean of marks of the students of three divisions of Class X.
Question
The mean of marks secured by 45 students in division A of class X is 69, 65 students of division B is 65 and that of 50 students of division C is 63. Find the mean of marks of the students of three divisions of Class X.
Total marks of division A=69× 45 (number of students× mean marks)=3105
Total marks of division B= 65× 65= 4225
Total marks of division C= 50× 63= 3150
Total marks of class x= 3105+4225+3150= 10480
Total number of students in class x= 45+65+50=160
Required mean marks=10480/160 = 65.5
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