Answer:
Due to their creditworthiness.
Step-by-step explanation:
A credit card can be defined as a small rectangular-shaped plastic card issued by a financial institution to its customers, which typically allows them to purchase goods and services on credit based on the agreement that the amount would be paid later with an agreed upon interest rate.
Generally, all interest card holders are required to make monthly minimum payments and they must be made promptly so as to have a good credit score.
A credit score can be defined as a numerical expression between 300 - 850 that represents an individual's financial history and credit worthiness. Therefore, a credit score determines the ability of a borrower to obtain credits from creditors.
This ultimately implies that, the higher your credit score, the lower and better is your interest rate or annual percentage rate (APR).
Hence, the reason why the same credit card may have two different interest rates, of 10.50% and 17.50%, for two different adults is due to their creditworthiness (credit score).