Use the image to answer the question.
A coordinate plane shows the x-axis, labeled as hours, ranging from 0 to 6 in increments of 1 and the y-axis, labeled as gallons, ranging from 0 to 240 in increments of 20. A line segment joins four plotted points. The coordinates of the plotted points are left parenthesis 0 comma 200 right parenthesis, left parenthesis 1 comma 160 right parenthesis, left parenthesis 3 comma 80 right parenthesis, and left parenthesis 5 comma 0 right parenthesis.
The graph shows the number of gallons in a wading pool that is being drained. Using the points (1,160) and (3,80) as (x1,y1) and (x2,y2) , what is the rate of change in the number of gallons in the pool after each hour has passed?
To find the rate of change, we can use the formula:
Rate of change = (y2 - y1) / (x2 - x1)
Plugging in the values from the points (1,160) and (3,80):
Rate of change = (80 - 160) / (3 - 1)
Rate of change = -80 / 2
Rate of change = -40
Therefore, the rate of change in the number of gallons in the pool after each hour has passed is -40 gallons per hour.