When a bank gives you a loan of 300.000 euro's, they don't have to have 300.000 on their books... They can just create "virtual money" which they loan out to you. IIRC, the percentage is actually a little less than 10%. So, a bank can have 30.000 on it's books, and still give out a 300.000 loan AND get 279.000 in intrest. They don't double their money, they actually multiply their investment by a factor >9...
Sorry, but this is completely inaccurate! Simple real-world personal example from 2017
I've sold my house to a guy who took a mortgage to buy the old apartment, the price was 140 000E, he took that loan, the bank wired me the money, the full 140 000E, and I spend it like the next day buying my new apartment in which I live now.
So, where are the virtual money and how did the bank manage to pay me the entire amount when they deal only with 10%?
You forget that it's not the bank that's selling you this, the bank needs to pay the actual owner of the house that can go the next day out to Las Vegas and gamble and whore all the sum in a day, and the last time I checked neither casino nor brothels take virtual money!