The mean of marks secured by 50 students in division A of class X is 61, 25 students of division B is 57 and that of 50 students of division C is 55. What will be the mean of marks of the students of three divisions of Class X?
Total marks secured by 50 students in division A = 50 $$\times$$ 61 = 3050
Total marks secured by 25 students in division B = 25 $$\times$$ 57 = 1425
Total marks secured by 50 students in division C = 50 $$\times$$ 55 = 2750
=> Mean of marks of the students of three divisions of Class X = $$\frac{(3050 + 1425 + 2750)}{(50 + 25 + 50)}$$
= $$\frac{7225}{125} = 57.8$$
=> Ans - (D)
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