The marks obtained in mathematics by 30 students of Class X of a certain school are given in the table below. Find the mean of the marks obtained by the students.

Step 1: Recall the formula of the mean of the grouped data
NOTE: The mean (or average) of observations is the sum of the values of
all the observations divided by the total number of observations.
Let x_1, x_2, x_3............, x_n be observations with respective
frequencies f_1, f_2,............f_n
Mean = \frac{f_1x_1 + f_2x_2 + ........f_nx_n}{f_1 + f_2 +..........+ f_n}
or
Mean = \frac{\Sigma f_ix_i}{\Sigma f_i}
Step 2: Re-organize given data in the table and find the sum of all observations.
Sum of the values of all the observations \Sigma f_ix_i = 1779
Total number of observations \Sigma f_i = 30
So, the mean = \frac{1779}{30}
Mean = 59.3