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Question 1144180: Deandre is driving to Memphis. Suppose that the distance to his destination (in miles) is a linear function of his total driving time (in minutes). Deandre has
70
miles to his destination after
20
minutes of driving, and he has
53.8
miles to his destination after
38
minutes of driving. How many miles will he have to his destination after
46
minutes of driving?
Found 2 solutions by greenestamps, josgarithmetic:
Answer by greenestamps(13200)   (Show Source):
You can put this solution on YOUR website!
There are many ways to solve this. I'll show one way; I expect other tutors will respond showing different ways.
When you have seen different ways to solve a particular type of problem, try them all and see what "works" for you. Of course the best course is to understand all the different methods. The more tools you have in your tool bag, the more you can do....
He has 70 miles left after 20 minutes of driving and 53.8 miles left after 38 minutes of driving.
So in 38-20=18 minutes he has driven 70-53.8=16.2 miles; his rate is 16.2/18 = 0.9 miles per minute.
So in the next 46-38=8 minutes, he will drive another 8(0.9) = 7.2 miles; the remaining distance will then be 53.8-7.2 = 46.6 miles.
That's the path to the solution that occurred to me first upon reading the problem....
Answer by josgarithmetic(39617)  (Show Source):
You can put this solution on YOUR website! Points (x,y) for (minutes, distance_remaining)
(20,70) and (38,53.8)
Simplify and solve for y in terms of x.
Substitute 46 for x, for the question and evaluate y.
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