1. What is the annual income if the income and the remaining money are used for savings?
2. If you use the remaining money and part of the loan to buy a house, what is the average annual income of the rent and value-added part?
Subtract the two and substitute the current economic indicators into the equation. If the function is greater than zero, it can be saved; If it is less than zero, you can borrow money to buy a house.
To do better, we can estimate the distribution of the probability of rising house prices, and then find the mathematical expectation.
In fact, it is also a simple income and expenditure model.