Thank you for the answer. So why do some of them say they would rather get 40% than 20% because it's a risky investment if the majority shareholder can take all the money to himself and the company and 0 to the investor?

Here is a very important lesson private companies. If you don't own 50.01% of the company you essentially don't own anything. The majority shareholder can pay themselves a large salary and use up all the profit, so that you get 20% of nothing. You mentioned Shark Tank... why to you think Mr, Marvelous - Kevin O'Leary often wants to be paid a royalty on every item so he gets his money out. Until you have a separate contract on how you are going to be paid.... you can easily be left holding the bag.

I got this doubt after watching Shark Tank so here it goes:

Let's say I invest 100k for 20% of this company. They use 150k to manufacture their product and then they sell it for 450k. So it's 300k in profit. Do I get my 20% of that profit? What if they decide to reinvest it on stock?