How do you Decompose 4/10 as the sum of unit fractions?

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?

What is r i 4.5+10r=-6.5 with work pls

I’m still confused on how to work the percentages