Question

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.

40 gal./hr.
40 gal./hr.

140
gal./hr.
Start Fraction 1 over 40 End Fraction gal./hr.

−140
gal./hr.
negative Start Fraction 1 over 40 End Fraction gal./hr.

Answer 1

Rate of change = (80 − 160) / (3 − 1) = −80/2 = −40, so −40 gallons per hour (the pool is losing 40 gal/hr).