SOLUTION: Suppose that the weight (in pounds) of an airplane is a linear function of the total amount of fuel (in gallons) in its tank. When graphed, the function gives a line with a slope o

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Suppose that the weight (in pounds) of an airplane is a linear function of the total amount of fuel (in gallons) in its tank. When graphed, the function gives a line with a slope o      Log On


   



Question 295935: Suppose that the weight (in pounds) of an airplane is a linear function of the total amount of fuel (in gallons) in its tank. When graphed, the function gives a line with a slope of 5.9.
With 54 gallons of fuel in its tank, the airplane has a weight of 2418.6 pounds. What is the weight of the plane with 26 gallons of fuel in its tank?

Answer by nerdybill(7384) About Me  (Show Source):
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Suppose that the weight (in pounds) of an airplane is a linear function of the total amount of fuel (in gallons) in its tank. When graphed, the function gives a line with a slope of 5.9.
With 54 gallons of fuel in its tank, the airplane has a weight of 2418.6 pounds. What is the weight of the plane with 26 gallons of fuel in its tank?
.
We know it is a linear function with a slope of 5.9 and they give us one data point:
(54, 2418.6)
.
Plug it into the "point-slope" form of a line:
y - y1 = m(x - x1)
y - 2418.6 = 5.9(x - 54)
y - 2418.6 = 5.9x - 318.6
y = 5.9x + 2100
f(x) = 5.9x + 2100 (this is our function)
.
Now we can answer:
What is the weight of the plane with 26 gallons of fuel in its tank?
f(26) = 5.9(26) + 2100 = 2253.4 pounds