Loanshark

My mother needed to break her $50 note. She decided to break her $50 with her granddaughters. But each of them didn't have enough $10 notes in their banks to exchange with her $50. My mother then decided to borrow $20 each from them and would return them once she breaks her $50 note. Juliane was waiting to go school when this happened. She looked thoughtfully at her grandmother and the following conversation exchange occurred.

Juliane: Ah Ma, you can take my $20.
Grandma: I give you back later, ok?
Juliane: No need to give back.
Grandma: You are such a good girl.
Juliane: You can give me the $50 now so no need to give me back later.

Both my mother and I were speechless. Borrow $20, return $50! How many percent increase in interest is that?! Oh dear, a potential loanshark in the making. :(