Calvin is mixing colored gravel for the bottom of his fish tank. he mixes 12 pounds of gravel weigh 3 pounds of purple gravel. how much blue gravel is used per pound of purple gravel?

Average salary for a medical assistant is $31,220 which is a 20% income tax bracket how much money would they pay in income tax?

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?

One number is 4 less than 3 times a second number. if 3 more than two times the first number is decreased by 2 times the second number, the result is 11. use the substitution method. what is the first number?