Algebra
posted by Roger .
Austin drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took
8 hours. When Austin drove home, there was no traffic and the trip only took
5 hours. If his average rate was
21 miles per hour faster on the trip home, how far away does Austin live from the mountains?
Do not do any rounding.

Algebra 
Reiny
speed on first leg  x mph
speed on return trip  x+21 mph
distance on first leg = 8x
distance for return leg = 5(x+21)
but the distances are equal, so
8x = 5(x+21)
8x = 5x + 105
3x=105
x = 35
distance = 8(35) = 280 miles 
Algebra 
Reiny
Just realized I did this same question a few weeks back
http://www.jiskha.com/display.cgi?id=1443062344
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