The slope can be used to represent the average rate of change, or how much one quantity changes, on average, relative to the change in another quantity. An example of a slope that changes in real-life involves units of measure such as beats per minute or kilowatts per hour. Over a 45-day period, the amount of propane in a tank that stores propane for heating a home decrease from 500 gallons to 344 gallons.

1. Use a graph or the slope formula to show the average rate of change in the amount of propane used over the 45-day period.
2. Show all work.
3. Explain what your solution represents in the context of the situation.