SOLUTION: It takes you 3 hours to drive to a concert 135 miles away. You drive 55 miles per hour on highways and 40 miles per hour the rest of the time. How much time did you spend driving a

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: It takes you 3 hours to drive to a concert 135 miles away. You drive 55 miles per hour on highways and 40 miles per hour the rest of the time. How much time did you spend driving a      Log On


   

Question 365764: It takes you 3 hours to drive to a concert 135 miles away. You drive 55 miles per hour on highways and 40 miles per hour the rest of the time. How much time did you spend driving at each speed?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
x = time on h-ways, y = rest of the time.
Then x+y = 3 and 55x + 40y = 135. By direct substitution,
55x + 40(3-x) = 135,
55x+ 120-40x = 135,
15x = 135-120,
15x = 15,
x = 1, he drove 1 hr on h-ways, and 2 hours others.