That's funny.
If they need 10% in reserves they can either take that original $10,000 keep $1,000 in the vault and loan out $9,000.
Excellent! Yes! Correct!
Or they can keep all $10,000 in the vault and loan out $100,000.
Bzzzt! Wrong! Thanks for playing.
Try to follow the math. If the Fed requires you to keep 10% of all your deposits as a reserve and you get a deposit of $10,000 then your reserve requirement is $10,000 x 0.1 or $1,000. You seemed to understand that.
Now, if you're keeping $10,000 in the vault, how in the name of public school math do you get $100,000 to loan out? Take your time. Walk through the steps one by one.
Sorry. that is precisely what they do. The rules allow them to loan out 10 times what they have in the vault. That’s exactly what they do.
Seriously.
Ask your bank manager Monday.