Please help, thank you so much !!

What is the difference between the predicted value and the actual value

Sarah took the advertising department from her company on a round trip to meet with a potential client. including sarah a total of 11 people took the trip. she was able to purchase coach tickets for $280 and first class tickets for $1280. she used her total budget for airfare for the trip, which was $6080. how many first class tickets did she buy? how many coach tickets did she buy?

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.