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Question
In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score
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Solution
Total marks of 10 students = 10 × 75 = 750
Total marks of 12 students = 12 × 60 = 720
Total marks of 8 students = 8 × 40 = 320
Total marks of 3 students = 3 × 30 = 90
Total marks of (10 + 12 + 8 + 3) 33 students
= 750 + 720 + 320 + 90
= 1880
Mean of marks = `1880/33`
= 56.97 or 57 approximately
Aliter:
Total number of students = 10 + 12 + 8 + 3
= 33
Mean of their marks
= `"Total marks"/"Number of students"`
= `(10 xx 75 + 12 xx 60 + 8 xx 40 + 3 xx 30)/33`
= `(750 + 720 + 320 + 90)/33`
= `1880/33`
= 56.97 or 57 approximately
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