Solve the system of equations. 7r + 22k = 101 8r + 20k = 100 What is the value of r? A. 3 miles B. 5 miles C. 7 miles D.8 miles MA.912.A.3.14: Solve systems of linear equations and inequalities in two and three variables using graphical, substitution, and elimination methods. Solve the system of equations: 30c + 50d = 290 50c + 40d = 310 What is the value of c? A. B. C. D. 3 4 5 6 MA.912.A.3.14: Solve systems of linear equations and inequalities in two and three variables using graphical, substitution, and elimination methods. John is training for a competition in which athletes will run and bike several miles. If John can run a mile in 7 minutes and bike a mile in 4 minutes, he will be able to finish the race in 90 minutes. If he can run a mile in 8 minutes and bike a mile in 3 minutes, he will be able to cover the same distance in just 84 minutes. In the equations below, r represents the number of miles run, and b represents the number of miles biked. 7r + 4b = 90 8r + 3b = 84 How many miles will John run during the race? A. 6 miles B. 7 miles C. 8 miles D. 12 miles MA.912.A.3.14: Solve systems of linear equations and inequalities in two and three variables using graphical, substitution, and elimination methods. According to government standards, a 100-gram piece of ''extra lean'' meat must contain 425 or fewer calories. A piece of extra lean meat contains 190 grams of protein and 10 grams of fat, for a total of 850 calories. A second piece of meat is the same weight, but it is not extra lean. This piece of meat contains 180 grams of protein and 20 grams of fat, but it has a total of 900 calories. In the equations below, f represents the number of calories in a gram of fat, and p represents the number of calories in a gram of protein. 190p + 10f = 850 180p + 20f = 900 How many calories are in a gram of protein? A. 4 B. 5 C. 8 D. 9 MA.912.A.3.14: Solve systems of linear equations and inequalities in two and three variables using graphical, substitution, and elimination methods. During a recent campaign, a candidate purchased two television commercials and one radio commercial for $29,250 in September. In October, she spent $62,250 on four television ads and three radio ads. In the equations below, r represents the cost of one radio commercial and t represents the cost of one television commercial. 2t + r = 29,250 4t + 3r = 62,250 What is the cost, in dollars, of one television commercial? A. B. C. D. $ 3,750 $ 12,750 $ 16,500 $ 22,550 MA.912.A.3.14: Solve systems of linear equations and inequalities in two and three variables using graphical, substitution, and elimination methods.