Question 598472: Mary is driving to San Francisco. Suppose that the remaining distance to drive (in miles) is a linear function of her driving time (in minutes). When graphed, the function gives a line with a slope of -0.9 .
Mary has 75 miles remaining after 50 minutes of driving. How many miles will be remaining after 64 minutes of driving?
Answer by htmentor(1343)   (Show Source):
You can put this solution on YOUR website! Mary is driving to San Francisco. Suppose that the remaining distance to drive (in miles) is a linear function of her driving time (in minutes). When graphed, the function gives a line with a slope of -0.9 .
Mary has 75 miles remaining after 50 minutes of driving. How many miles will be remaining after 64 minutes of driving?
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The function will have the form d = m*t + d0
where d0 = the distance remaining at t=0 and m is the slope
Given: m = -0.9, d=75,t=50
Use this information to solve for d0:
75 = -0.9*50 + d0
d0 = 75 + 45 = 120
So the equation is d = -0.9t + 120
Solve for d when t=64:
d = -0.9*64 + 120
d = 62.4 minutes
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