Find the mean marks of the students from the following cumulative frequency distribution:
Marks:          Below Below Below         Below Below Below Below         Below Below Below 10     20        30        40         50        60        70         80        90        100 No. of Students        5          9         17        29        45        60         70        78        83        85

Explanation

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

### Step 1: Convert Cumulative Frequency to Frequency
We need to convert the cumulative frequency into actual frequency for each class interval. The frequency for each class can be calculated by subtracting the cumulative frequency of the previous class from the cumulative frequency of the current class.

| Marks (Class Interval) | Cumulative Frequency | Frequency (f) |
|------------------------|----------------------|----------------|
| Below 10 | 5 | 5 |
...