SOLUTION: Jeff recently drove to visit his parents who live 390 miles away. On his way there his average speed was 25 miles per hour faster than on his way home (he ran into some bad weather

Question 998641: Jeff recently drove to visit his parents who live 390 miles away. On his way there his average speed was 25 miles per hour faster than on his way home (he ran into some bad weather). If Jeff spent a total of 13 hours driving, find the two rates.
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Distance = 380 miles
return speed =x
going speed = x+25
Time forward + time return = 13
t=d/r

390(x+25)+390x = x(x+25)*13
390x+9750 +390x=(x^2+25x)*13
780x +9750 = 13x^2+325x
13x^2-780x+325x-9750=0
13x^2-455x-9750=0
solve to get return speed = 50 mph

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