SOLUTION: joe and louise are making a drive from san diego to salt lake city. After four hours of driving they are 507 miles drom salt lake city. eight hours into their trip they are only 26

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Question 877284: joe and louise are making a drive from san diego to salt lake city. After four hours of driving they are 507 miles drom salt lake city. eight hours into their trip they are only 267 miles away from their destination. Assume theu average the same speed for entire trip.What's is the expression to find how many hours will they reach Salt Lake City from the time they left San Diego
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joe and louise are making a drive from san diego to salt lake city.
After four hours of driving they are 507 miles drom salt lake city.
eight hours into their trip they are only 267 miles away from their destination. Assume they average the same speed for entire trip.
What's is the expression to find how many hours will they reach Salt Lake City from the time they left San Diego
:
Find the slope of a linear equation y = mx + b
x1=4; y1=507
x2=8; y2=267
:
m %28267-507%29%2F%288-4%29 = %28-240%29%2F4 = -60 is the slope
:
Y = -60x + b
Find b when x=4 and y=507
-60(4) + b = 507
-240 + b = 507
b = 507 - 240
b = 747
therefore the equation, x= hrs, y=dist from Salt Lak
y = -60x + 747
:
"What's is the expression to find how many hours will they reach Salt Lake?"
:
When they reach Salt lake y = 0, therefore
-60x + 747 = 0
-60x = -747
x = -747/-60
x = 12.45 hrs