Mohan withdrew a fixed amount (₹20,000) every month starting from 1st July, 2023 to 31st March, 2024.
This constitutes **monthly drawings for 9 months**.
When monthly drawings are made at the **beginning of each month**, the average period = 6.5 months.
Why?
For beginning of each month, average time = $\dfrac{n+1}{2}$ months
Here, $n = 12 - 6 + 1 = 9$ months
$\Rightarrow$ Average period = 6.5 months
Hence, interest will be charged for 6.5 months.