Step 1: Use the EOQ formula.
The Economic Order Quantity (EOQ) is given by the formula:
\[
EOQ = \sqrt{\frac{2DS}{H}}
\]
Where:
- \( D \) is the annual demand (16,000 units),
- \( S \) is the ordering cost per order (Rs 100),
- \( H \) is the holding cost per unit per year (10\% of the cost of one unit, which is \( 0.1 \times 2 = 0.2 \)).
Step 2: Calculate EOQ.
Substitute the given values into the formula:
\[
EOQ = \sqrt{\frac{2 \times 16000 \times 100}{0.2}} = \sqrt{\frac{3200000}{0.2}} = \sqrt{16000000} = 4004 \, \text{units}
\]
Final Answer:
\[
\boxed{4004 \, \text{units}}
\]