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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

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

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

−40 gal./hr.
negative 40 gal./hr.

40 gal./hr.
40 gal./hr.
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Answer 1

The rate of change can be calculated using the formula:

Rate of change = (change in y) / (change in x)

So, plugging in the values:

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. So the correct answer is -40 gal./hr.