1 1/3 * 1 3/4 please help me with this

Find the given elements if matrix d:

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?

See attachment below and find the equivalent of tan(∠qsr)