Okay, I have tried for 2 hours on this, and I'm sure it is going to turn out to be one of those questions where it is a lot simpler than it seems but, here goes, I would love for anyone to help and explain how they did it too.
7. Your mother is pleased you are going to make an effort to make your bed, so she agrees that each day you make your bed, she will nag you half as long about your other household chores. She currently nags you for 120 minutes a day.
a) If n is the day number, and M is the number of minutes spent nagging, write a relation for n and M
b) How much will your mother nag on the 28th day?