Megan's science teacher gave each student in her class a 20.0 gram sample of sedimentary rock. each student is required to verify the rock sample by taking four mass measurements. which measurement is the most accurate of the four recorded?
a) 19.012 grams
b) 19.0122 grams
c) 19.02 grams
d) 19.12 grams

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?