Answer:
She spend $0.7435 per month.
Step-by-step explanation:
Consider the provided information.
Regina spent $45.50 over 612 months on music downloads.
she spent the same amount of money each month.
Let she spent x amount each month.
She spent x amount each month for 612 months and in total she spent $45.50
This can be written as: 
Divide both sides by 612.


Hence, she spend $0.0743 per month.