Answer the question (pre algebra)

Charlie is a car salesman he earns $800 plus a 9% commission on all of her sales for the week if charlie receive the payment for $1960 this week how much where is total sales

Liam's parents are driving three times as fast as liam is biking, but they left later than he did. if his parents caught up with him two hours after he left, how much later than liam did they leave?

Which recursive formula can be used to determine the total amount of money earned in any year based on the amount earned in the previous year? f(n+1)=f(n)+5