<PRE><B>Question 667585</B>
A car travels 200 miles in the same time it takes a car traveling 10 miles per hour slower to travel 150 miles. give the speed of each car 
I tried to solve it like this: 
x+200=x+150-10
x+200=x+140
-140 -140
----------------
x+60=x
-x -x
----------------
60=x 
Thus, 60 mph being the speed of the first car, and 50 mph the speed of the second car. 
That was incorrect.
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d = r*t
t = d/r
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t = 200/r = 150/(r-10)
200*(r-10) = 150r
200r - 2000 = 150r
50r = 2000
r = 40 mi/hr
r-10 = 30 mi/hr
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