SOLUTION: a car traveled at an average rate of 40 mph and then reduced its average rate to 30mph for the rest of the trip. if the 180 mile trip took five hour, determine how long the car tra

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Question 81580: a car traveled at an average rate of 40 mph and then reduced its average rate to 30mph for the rest of the trip. if the 180 mile trip took five hour, determine how long the car traveled at each rate.
Found 2 solutions by checkley75, scott8148:
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
40X+30(5-X)=180
40X+150-30X=180
10X=180-150
10X=30
X=3 HOURS @ THE 40 MPH RATE &
5-3=2 HOURS @ THE 30 MPH RATE.
PROOF
40*3+30*2=180
120+60=180
180=180

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
let t equal the time at 40 mph ... so 5-t is the time at 30 mph ... the total distance is the sum of the distances at the two rates

40*t+30*(5-t)=180 ... 40t+150-30t=180 ... 10t=30 ... t=3 ... 3 hrs at 40 mph and 2 hrs at 30 mph