Step 1: Monthly drawings = ₹ 20,000
Number of months = 12
Total drawings in the year = ₹ 20,000 × 12 = ₹ 2,40,000
Step 2: Interest on drawings when withdrawn at beginning of every month:
\[
\text{Interest} = \frac{Total Drawings × Rate × (n+1)}{2 × 12 × 100}
\]
\[
= \frac{2,40,000 × 6 × 13}{2 × 12 × 100} = ₹ 3,600
\]