ben walks at a rate of 3 miles per hour. he runs at a rate of 6 miles per hour. in one week his combined distance is 21o miles. what is an equation that relates the number of hours that ben walks to the number or miles ben runs?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

12.0 million metric tons of beef produced annually in the u.s. out if 65.1 mikkion metric tons of produced annually worldwide

What are the solutions of the equation x4 + 6x2 + 5 = 0? use u substitution to solve.