Thomas, a waiter at a local restaurant, is paid $4 an hour plus tips. his friend marie works at a local bookstore for $12 an hour. marie and thomas work the same number of hours. if thomas made $120 in tips and both made the same amount of money, how many hours did thomas and marie each work?

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).