The annual return on investment is ((3300-40000/24)*12)/80000=25%
This is approximately equal to, probably 25%. This annual return, It's already very high.
Nowadays, the annual return rate for renting a house in the city is about 5%, and the annual return rate for bank loans is about 5%-8%. Even including gray income, it will not exceed 16%.
Let me explain, the annual rate of return is actually: [The amount of money you earn every year (3300*12)]/[The money you initially invested 80,000], but this is when you don’t have 80,000 yuan. Based on the change, your 80,000 yuan will become 40,000 yuan in 2 years, which means that you will reduce it by 20,000 yuan every year. Then your annual income (3300*12) minus 20,000 divided by 80,000 is your annual return.
You are looking back at this formula "((3300-40000/24)*12)/80000=25%"
40000/24 ??is your monthly change. 3300-40000/24 ??is your actual monthly income. This amount multiplied by 12 is your actual annual income. Divided by your total investment, this is your annual rate of return.