SOLUTION: You drove from your home to dallas at an average speed of 60 miles per hour and returned home at an average speed of 45 miles per hour.if the total driving time was 21 hours, how

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Question 707780:
You drove from your home to dallas at an average speed of 60 miles per hour and returned home at an average speed of 45 miles per hour.if the total driving time was 21 hours, how far is it from your home to dallas.
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
d=rt
d=60t to Dallas.
d=45(21-t) from Dallas.
60t=45(21-t)
60t=945-45t
60t+45t=945
105t=945
t=945/105
t=9 hours for the trip to Dallas.
21-9=12 hours from Dallas.
Proof:
60*9=45*12
540=540