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?
(1 point)
Responses
−40 gal./hr.
negative 40 gal./hr.
−140 gal./hr.
negative Start Fraction 1 over 40 End Fraction gal./hr.
140 gal./hr.
Start Fraction 1 over 40 End Fraction gal./hr.
40 gal./hr.
To find the rate of change in the number of gallons in the pool after each hour has passed, we need to determine the change in y (gallons) divided by the change in x (hours).
In this case, the change in y is 160 - 80 = 80 gallons (y2 - y1) and the change in x is 3 - 1 = 2 hours (x2 - x1).
Therefore, the rate of change is 80/2 = 40 gallons per hour.
Thus, the correct answer is 40 gal./hr.