Question 91

The mean of marks secured by 45 students in division A of class X is 56, 40 students of division B is 52 and that of 40 students of division C is 50. Find the mean of marks of the students of three divisions of Class X.

Solution

Total marks secured by 45 students in division A = 45 $$\times$$ 56 = 2520

Total marks secured by 40 students in division B = 40 $$\times$$ 52 = 2080

Total marks secured by 40 students in division C = 40 $$\times$$ 50 = 2000

=> Mean of marks of the students of three divisions of Class X = $$\frac{(2520 + 2080 + 2000)}{(45 + 40 + 40)}$$

= $$\frac{6600}{125} = 52.8$$

=> Ans - (C)

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