Find the mean marks of students from the following cumulative frequency distribution:
marks              No. of Students                        Marks                        No. of Students 0 and above 10 and above 20 and above 30 and above 40 and above 50 and above         80 77 72 65 55 43  60 and above 70 and above 80 and above 90 and above 100 and above       28 16 10 8 0

Explanation

To find the mean marks of students from the given cumulative frequency distribution, we will follow these steps:

### Step 1: Create a frequency distribution table
We will first convert the cumulative frequency distribution into a frequency distribution. The cumulative frequencies provided are:

- 0 and above: 80
- 10 and above: 77
- 20 and above: 72
...