The marks obtained by 30 students of Class X of a certain school in a Mathematics paper consisting of 100 marks are presented in table below. Find the mean of the marks obtained by the students. Marks obtained (x_i): 10, 20, 36, 40, 50, 56, 60, 70, 72, 80, 88, 92, 95 Number of students (f_i): 1, 1, 3, 4, 3, 2, 4, 4, 1, 1, 2, 3, 1