What is a Loan?

Aaron is disappointed when he finds his crisps missing at school. His friend Amira offers to share hers but introduces the concept of a loan, explaining that he must return the crisps with extra. Amira further explains loans, interest, and why people take loans for big purchases. She describes the process of applying for a loan, including credit checks. Aaron humorously applies this concept to his sister, offering her a 'crisp loan.'

What process did Amira describe for getting a loan from a bank?

What was Aaron's idea when his sister asked for crisps?