Question

Find the weighted mean of marks obtained by a student in certain examination if he has secured $75,80,67,90$ marks in English, Tamil, Mathematics, social Science respectively, having corresponding weights $3,2,2,1.$

• A. $75.16$
• B. $76.12$
• C. $62.17$
• D. $78.12$

Answer 1

The correct option is B $76.12$

Subject	Marks obtained	Weights $w_i$	$x_i{w}_i$
English	$75$	$3$	$225$
Tamil	$80$	$2$	$160$
Mathematics	$67$	$2$	$134$
Social science	$90$	$1$	$90$
		$\Sigma w_i=8$	$\Sigma x_i{w}_i=609$

Weighted Arithmetic mean $=$ $\frac{\Sigma x_i{w}_i}{\Sigma w_i}$ $=609/8$
Weighted Arithmetic mean $=76.125$