Question

The following table shows the marks obtained by 5 students in a classroom, find the average marks of the classroom.

$$\begin{array}{cc}Marks& Frequency\\ 98& 1\\ 65& 1\\ 88& 2\\ 54& 1\end{array}$$

• A. 76.6
• B. 77.6
• C. 78.6
• D. 78.9

Answer 1

The correct option is C

78.6

So, the total marks obtained by 5 students of the classroom are 98 + 65 + 176 + 54 = 393. Now, the mean or average value of marks can be calculated by dividing the summation of marks obtained by each student i.e. 393 divided by the total number of students i.e. 5. So, we get $\frac{393}{5}$= 78.6

$$\begin{array}{ccc}Marks\left(x_i\right)& Frequency\left(f_i\right)& x_i{f}_i\\ 98& 1& 98\\ 65& 1& 65\\ 88& 2& 176\\ 54& 1& 54\\ Total& \sum f_i=5& \sum x_i{f}_i=393\end{array}$$

So, mean or average = $\frac{\sum 393}{\sum 5}$= 78.6