The mean of marks secured by 50 students in d | vedclass

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Question

(D) The mean of marks for all $3$ divisions of Class $X$ is calculated using the formula for the combined mean:Combined Mean = $\frac{\sum (n_i 	imes

Vedclass · Accepted Answer

$57.8$

Vedclass · Answer

(D) The mean of marks for all $3$ divisions of Class $X$ is calculated using the formula for the combined mean:Combined Mean = $\frac{\sum (n_i 	imes \bar{x}_i)}{\sum n_i}$Given:Division $A$: $n_1 = 50$,$\bar{x}_1 = 61$Division $B$: $n_2 = 25$,$\bar{x}_2 = 57$Division $C$: $n_3 = 50$,$\bar{x}_3 = 55$Total sum of marks = $(50 	imes 61) + (25 	imes 57) + (50 	imes 55)$$= 3050 + 1425 + 2750 = 7225$Total number of students = $50 + 25 + 50 = 125$Mean = $\frac{7225}{125} = 57.8$

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 $X$?

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