SOLUTION: Jim is driving to Atlanta. Suppose that the remaining distance to drive (in miles) is a linear function of his driving time (in minutes). When graphed, the function gives a line wi

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Question 311461: Jim is driving to Atlanta. Suppose that the remaining distance to drive (in miles) is a linear function of his driving time (in minutes). When graphed, the function gives a line with a slope of -0.9
Jim has 74 miles remaining after 31 minutes of driving. How many miles were remaining after 19 minutes of driving?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Suppose that the remaining distance to drive (in miles) is a linear function of
his driving time (in minutes).
When graphed, the function gives a line with a slope of -0.9
Jim has 74 miles remaining after 31 minutes of driving.
:
Use the form mx + b = y; y=dist, x=minutes; m=-.9
When x = 31 and y = 75, find b
-.9(31) + b = 74
-27.9 + b = 74
b = 74 + 27.9
b = 101.9;
then: y = -.9x + 101.9 is the equation, a graph of this looks like this
+graph%28+300%2C+200%2C+-10%2C+90%2C+-20%2C+125%2C+-.9x%2B101.9%29+
:
How many miles were remaining after 19 minutes of driving?
y = -.9x + 101.9
x = 19 mi
y = -.9(19) + 101.9
y = -17.1 + 101.9
y = 84.8 miles remaining after 19 min