Dividends are calculated according to the assumed high, medium and low grades. Because the company's profits are uncertain and often change. So let's assume an interest rate, so that you can probably know what will happen in the future. These are all calculated by some specialized professionals. So we only know these details, but one thing is that the company will use 70% of its profits to pay dividends every year.
Suppose you invest 40 thousand and 8000.
Bonus payable: 8000/40000 = 0.2
0.2x 100%=20%
That is, the bonus you win is 20%.
The dividends between you can be stipulated in the signed shareholder agreement.