The mean mark obtained by the 40 students is 37.25.
The marks obtained by 40 students out of 50 in a class are given below in the table.
| Marks (in $) | Number of Students |
| 42 | 7 |
| 36 | 10 |
| 30 | 13 |
| 45 | 8 |
| 50 | 2 |
Mode: The mode is the most frequent mark. In this case, the mode is 30, as it is the mark that occurs the most times (13 times).
Mean: The mean is the average of all the marks. To calculate the mean, we add up all the marks and divide by the number of students.
Mean = (42 * 7 + 36 * 10 + 30 * 13 + 45 * 8 + 50 * 2) / 40
= 37.25
Therefore, the mean mark obtained by the 40 students is 37.25.