SOLUTION: The rate at which water evaporates from a certain reservoir depends on the air temperature. The table below shows the number of acre-feet (af) of water per day that evaporates from

Question 1128013: The rate at which water evaporates from a certain reservoir depends on the air temperature. The table below shows the number of acre-feet (af) of water per day that evaporates from the reservoir for various temperatures in degrees Fahrenheit.
Temperature (�F) (af)
40 960
60 1800
70 2220
85 2850
(a) Find a linear model for the number of acre-feet of water that evaporates as a function of temperature.
E(T) =
(b) Explain the meaning of the slope of this line in the context of this problem.
The value of the slope means that an additional af evaporates for a 1�F in temperature.
(c) Assuming that water continues to evaporate at the same rate, how many acre-feet of water will evaporate per day when the temperature is 75�F?
af
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
slope is change in y/change in x
840/20=42, and that is the slope between any two adjacent points.
use point slope formula for the model y-y1=m(x-x1) m slope and (x1, y1) point
y-960=42(x-40)
y=42x-720
E(T)=42 F - 720
every degree change F increases acre-feet evaporation by 42 af a day.
at 75 degrees it will be 42*75-720 or 2430 af a day.

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