SOLUTION: At 10:00AM a car left the service station on Route 209 heading south at 86knh. At 10:30 AM another car left the station and headed south at 80kmh. At what time were the cars 55km

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: At 10:00AM a car left the service station on Route 209 heading south at 86knh. At 10:30 AM another car left the station and headed south at 80kmh. At what time were the cars 55km      Log On

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Question 67697This question is from textbook
: At 10:00AM a car left the service station on Route 209 heading south at 86knh. At 10:30 AM another car left the station and headed south at 80kmh. At what time were the cars 55km apart? This question is from textbook

Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!

We'll first determine how many hours it takes for the cars to be 55 km apart and then add that to 10:30 AM to get our answer
When the difference between the distances the two cars will have traveled equals 55 km, then we will have our answer
distance(d) =rate(r) times time(t) or d=rt and t=d/r
Let x=number of hours that the 10:30 car has driven when they are 55 km apart
Then x+0.5= number of hours that the 10:00 car has driven
distance 10:30 car will have driven=80x
distance 10:00 car will have driven=86(x+0.5)
so our equation to solve is:
86(x+0.5)-80x=55 clear parens
86x+43-80x=55 subtract 43 from both sides
6x=12
x=2 hours
10:30 AM plus 2 hours=12:30 PM-----------------------answer we are looking for
CK
86*2+43= 215km
80*2=160km
215 km -160km=55km----------ck