An ultrasound technician sometimes uses microbubbles as a contrast agent to improve the clarity of ultrasounds. However, the technician has a limited time to work, since the ultrasound process quickly destroys the microbubbles. The following expression represents the concentration, in microbubbles per milliliter, of the microbubble suspension remaining in a client t seconds after the technician has begun the ultrasound process. 100,000,000*0.5^t/120 Which expression shows the multiple of the concentration remaining each minute as a constant or coefficient?