The grade of a hill is its steepness represented as a percent. Jin tracks his walking speed up different hills. What does the rate of change, or slope, represent in this situation? A scatterplot with grade of hill as a percent on the x axis and walking speed in miles per hour on the y axis. About 20 points are plotted in a downward trend along with a line of best fit which begins at the point zero comma 3 point 5 and passes through the point 2 comma 3.

The rate represents an increase in speed for each 1% grade increase.

The rate represents a decrease in speed for each 1% grade decrease.

The rate represents a decrease in speed for each 1% grade increase.

The rate represents no change in speed for each 1% grade decrease.