Blake took his motorboat, which travels 36 miles per hour in still water, on a river. He traveled downstream (i. e., with the current) for 6 minutes. Then he turned off the motor and drifted with the current for 30 minutes. Finally, he turned his motor back on, turned around, and traveled upstream (i. e., against the current) for 15 minutes. Fill in the table below to find expressions for the number of miles Blake traveled downstream with his motor on, downstream with his motor off, and upstream. Use x to represent the current's speed in miles per hour.