Question 56

The mean of marks secured by 60 students in division A of class X is 64, 40 students of division B is 60 and that of 60 students of division C is 58. Find the mean of marks of the students of three divisions of Class X.

Solution

Total marks secured by 60 students in division A = 60 $$\times$$ 64 = 3840

Total marks secured by 40 students in division B = 40 $$\times$$ 60 = 2400

Total marks secured by 60 students in division C = 60 $$\times$$ 58 = 3480

=> Mean of marks of the students of three divisions of Class X = $$\frac{(3840 + 2400 + 3480)}{(60 + 40 + 60)}$$

= $$\frac{9720}{160} = 60.75$$

=> Ans - (D)

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