Henry bought a book for $10.34, and the sales tax was 8.25%. how much sales tax did henry pay on the book?
a. $0.88
b. $0.85
c. $0.75
d. $0.78

I'm confused on this could anyone me and show me what i need to do to solve it.

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?

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction