A plant is growing steadily and you decide to keep track of how tall it is. When you first plant it, it is...

5. A plant is growing steadily and you decide to keep track of how tall it is. When you first plant it, it is one inch tall. At 6 weeks the plant is 3 inches tall. What is the rate of change?
6. A submarine is diving and at one minute is 6 feet below sea level. At 7 minutes the submarine is 9 feet below sea level. What is the rate of change?
7. Your pet turtle is going for a walk and has travelled 10 feet in 9 minutes. You notice that at 12 minutes your turtle has travelled 14 feet. What is the rate of change?
8. A hot air balloon is rising and at 15 seconds is 25 feet in the air. At 45 seconds the balloon is 115 feet in the air. What is the rate of change?