Short answer type question :

Let us find the difference between upper class limit in median class and lower class limit of modal class of the above frequency distribution table.

Here, we need to find the median class and modal class.

Let us find median class.

Let us create a table.

Here, total sum of frequency, N = 77

⇒

⇒

Note in the table that, cf = 42 is just greater than 38.5.

⇒ Median class = 125 – 145

Now, let us find modal class.

For modal class, just check the greatest frequency.

Here, the greatest frequency = 20

⇒ Modal class = 125 – 145

Upper class limit of median class = 145

Lower class limit of modal class = 125

Difference = Upper class limit of median class – Lower class limit of modal class

⇒ Difference = 145 – 125

⇒ Difference = 20

Thus, answer is 20.