Interest on drawings is calculated as:
\[
\text{Interest on Drawings} = \text{Total Drawings} \times \text{Rate of Interest} \times \text{Average Time Period}.
\]
Rhea withdrew ₹ 30,000 twice during the year (at the beginning of each half-year). The average time period for each withdrawal is calculated as:
\[
\text{Average Time Period for First Withdrawal} = \frac{12}{12} = 1 \, \text{year},
\]
\[
\text{Average Time Period for Second Withdrawal} = \frac{6}{12} = 0.5 \, \text{year}.
\]
Now, calculate the interest for each withdrawal:
\[
\text{Interest for First Withdrawal} = ₹ 30,000 \times 10\% \times 1 = ₹ 3,000,
\]
\[
\text{Interest for Second Withdrawal} = ₹ 30,000 \times 10\% \times 0.5 = ₹ 1,500.
\]
The total interest is:
\[
\text{Total Interest} = ₹ 3,000 + ₹ 1,500 = ₹ 4,500.
\]