Question

In the following table, the number of students and their marks are given
$\begin{array}{ccccccc}\text{No. of students}& 8& 12& 20& 10& 6& 4\\ \text{Marks}& 20& 30& 40& 50& 60& 70\end{array}$
The mean score of students will be

• A. $41$
• B. $42$
• C. $40$
• D. $39$

Answer 1

The correct option is A $41$

Let the number of students be denoted by $f$ and marks be denoted by $x$
So, the mean score of students
$=\sum \frac{f_i{x}_i}{f_i}=\frac{8\times 20+12\times 30+20\times 40+10\times 50+6\times 60+4\times 70}{8+12+20+10+6+4}=\frac{2460}{60}=41$