The cafeteria sold pizza and burritos. Burritos sold for $3.50 each and pizza slices sold for $2.75 . A total of 20 items were sold and the cafeteria collected $61. How many pizza slices were sold

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?