Question

Mean marks of 60 students of a class are 63 and that of 40 other students are 60 . the means marks of all together are ?

Answer 1

Mean of marks of 60 students of a class = 63
Mean of marks of 40 other students of the class = 60

Total number of students = 100 


Mean = Sum of all marks / Number of students

63 = Sum of all marks / 60

Sum of all marks = 3780

for 40 students,

Mean = Sum of all marks / Number of students

60 = Sum of all marks / 40

Sum of all marks = 2400

Mean of 100 students = 2400 + 3780 / 100 = 61.8

Answer 2

Solution :-

Mean marks of 60 students = 63

Total marks of 60 students = 63*60

Total marks of 60 students = 3780

Mean marks of 40 other students = 60

Total marks of these 40 students = 60*40

Total marks of these 40 students = 2400

Total students = 60 + 40

= 100 students

Total marks of 100 students = 3780 + 2400

= 6180 marks

Mean marks of all the 100 students = 6180/100

= 61.8 marks

Answer.