SOLUTION: Carol drove for 3 hours on a two-lane state road. She then increased her speed by 25 miles per hour on the freeway and drove for 6 more hours. If the total trip was 510 miles, the

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Carol drove for 3 hours on a two-lane state road. She then increased her speed by 25 miles per hour on the freeway and drove for 6 more hours. If the total trip was 510 miles, the      Log On

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Question 766882: Carol drove for 3 hours on a two-lane state road. She then increased her speed by 25 miles per hour on the freeway and drove for 6 more hours. If the total trip was 510 miles, then what was her speed on the freeway?
Answer by ramkikk66(644) About Me  (Show Source):
You can put this solution on YOUR website!
Carol drove for 3 hours on a two-lane state road. She then increased her speed by 25 miles per hour on the freeway and drove for 6 more hours. If the total trip was 510 miles, then what was her speed on the freeway?
Ans:
Let her initial speed be x mph
Then, distance covered in the 2-lane road = 3*x (since she drove for 3 hours)
Speed on freeway = x+25
Distance covered in freeway, in 6 hours = (x+25)*6 = 6*x + 150
Total distance = 3*x + 6*x + 150 = 510 (given)
Simplifying
9*x = 510 - 150 = 360
x = 40
Speed in 2-lane road = 40 mph
Speed on freeway = 40 + 25 = 65 mph
:)