To determine the total monthly payments for the proposed alternative to buy, we need to calculate the monthly mortgage payments and add the other home ownership costs.

First, we need to calculate the loan amount. Since Jain is financing 80% of the purchase price, the loan amount would be:

Loan amount = 80% of ₹12.5 million = ₹10 million

Next, we can use the loan amount, interest rate, and loan term to calculate the monthly mortgage payments using the formula for a fixed-interest rate loan:

Monthly mortgage payment = (P * r) / (1 - (1 + r)^(-n))

Where P is the loan amount, r is the monthly interest rate (which is the annual interest rate divided by 12), and n is the total number of monthly payments (which is the loan term multiplied by 12).

Plugging in the values, we get:

Monthly mortgage payment = (10,000,000 * 0.1025/12) / (1 - (1 + 0.1025/12)^(-20*12)) = ₹103,125

So the monthly mortgage payment is ₹103,125.

Next, we need to add the other home ownership costs:

• Down payment opportunity cost: Jain is monetizing his fixed deposits and savings to finance the down payment, which are earning around 7% per year. So the opportunity cost of the down payment would be 7% of 20% of ₹12.5 million = ₹175,000 per year, or ₹14,583 per month.
• Stamp duty and other charges: Jain estimated that these would be 6% + 1% of the sale deed’s total value, which is ₹12.5 million. So the stamp duty and other charges would be 7% of ₹12.5 million = ₹875,000, or ₹72,917 per month.
• Property taxes: Jain estimated that he would have to pay ₹10,000 per year, or ₹833 per month.
• Brokerage expenses: Jain would have to pay 1% of the value of the property for the arranging and executing of the purchase of the property by his broker, which is ₹125,000. So the brokerage expenses would be ₹125,000 / 240 months (20 years) = ₹520.83 per month.
• Society charges: Jain would be required to pay a recurring society charge of ₹1,000 per month (including the use of parking facilities).

Adding all of these costs together, we get:

Total monthly payments = Monthly mortgage payment + Down payment opportunity cost + Stamp duty and other charges + Property taxes + Brokerage expenses + Society charges = ₹103,125 + ₹14,583 + ₹72,917 + ₹833 + ₹520.83 + ₹1,000 = ₹193,979.83

So the total monthly payments for the proposed alternative to buy would be ₹193,979.83.