Company X plans to spend $500,000 on 20 new computers. Each model A computer will cost $2,000, each model B $2,500, and each model C $3,500. Company X has decided that they need twice as many model A computers as Model B computers. How many of each kind of computers can the company buy?
A baseball park has 7000 seats. Box seats cost $6, grandstand seats cost $4, and bleacher seats cost $2. When all seats are sold, the revenue is $26,400. If the number of box seats is one-third the number of bleacher seats, how many seats of each type are there?
The population of a state was approximately 24 million in 1980, 30 million in 1990, and 34 million in 2000. Construct a model for this data by finding a quadratic equation whose graph passes through the points (0,24), (10,30), and (20,34).