Mohan's profit share is \( \frac{1}{5} \).
Mohan contributed ₹ 2,00,000 as goodwill premium.
This ₹ 2,00,000 represents his \( \frac{1}{5} \) share of the firm's total goodwill.
Therefore, the Total Goodwill of the firm is calculated as \( \frac{2,00,000}{1/5} = 2,00,000 \times 5 = ₹ 10,00,000 \).
Final Answer: ₹ 10,00,000