PLZ IN NEED OF HELP!!

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?

Hey free points ! people i have a few math questions on my profile consider looking at them i have to get done in 30 mins!

If the value of cos330°is√3/2 then find cos 165°.