How do you solve system of equations word problems?

The sum of three numbers is 91. the third number is 2 times the first. the first number is 7 less than the second. what are the numbers?

Georgia is building a patio he estimates that he can install 8 square feet of bricks every quarter-hour. how many square feet does georgia install in one hour?

Last month, Luke spent $1,300 on his mortgage (home loan payment), $320 for food, $280 on entertainment, $275 for his car payment, $60 on car insurance, and $75 on clothing.

A bag has 15 white marbles and 12 blue marbles. Allison will randomly select 1 marble from this bag. What is the probability that she will select a blue marble?

The students at Miami Senior High School are raising money for homecoming. The graph below shows the amount of money each class has raised so far. About what percentage of the money raised did the sophomore class earn? Money Earned for Homecoming

Prove 1 + cos (2 θ) 2 / cos (θ) = cos (θ) is an identity

2 inches of snow in 4 hours, what is the unit rate?

What is the solution set to the system of equations 10x+3y=43 -9x-y=-20 a.) (11,1) b.) (1,11) c.) (-1,11) d.) (11,-1)

Every three days Marco fills up his car with gas. Every eight days he washes his car. On what day will Marco go fill his car with gas and wash it?

After a new $28,000 car is driven off the lot, it begins to depreciate at a rate of 18.9% annually. Which function describes the value of the car after t years? 1) C (t) = 28,000 (0.158) ^t 2) C (t) = 28,000 (0.811) ^t 3) C (t) = 28.000 (1.