this is a algebra question

Question

Sarah took the advertising department from her company on a round trip to meet with a potential client. Including Sarah a total of 15 people took the trip. She was able to purchase coach tickets for $140 and first class tickets for $1030. She used her total budget for airfare for the trip, which was $8330. How many first class tickets did she buy? How many coach tickets did she buy?

Answer 1

f represents the number of first class tickets

15 - f represents the number of coach tickets

140f + 1030(15 - f) = 8330

 

Can you solve for f and answer?

 

Why does Sarah treat some of her department differently?