SOLUTION: The average speed of a train is 20 miles per hour faster than that of a car.In 8 hours and 40 minutes , the train covers the same distance that the car covers in 13 hours . Find th

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: The average speed of a train is 20 miles per hour faster than that of a car.In 8 hours and 40 minutes , the train covers the same distance that the car covers in 13 hours . Find th      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 88790: The average speed of a train is 20 miles per hour faster than that of a car.In 8 hours and 40 minutes , the train covers the same distance that the car covers in 13 hours . Find the average speed of each .
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The average speed of a train is 20 miles per hour faster than that of a car.In 8 hours and 40 minutes , the train covers the same distance that the car covers in 13 hours . Find the average speed of each .
:
Let s = speed of the car
Then
(s+20) = speed of the train
:
Change 8 hr 40 min to hrs: 8 + 40/60 = 8 & 2/3 hrs or 26/3 hrs
:
Distance = time * speed
:
car dist = train dist
13s = %2826%2F3%29%28s%2B20%29
:
Mult equation by 3, get rid of the denominator:
3(13s) = 26(s+20)
:
39s = 26s + 520
:
39s - 13s = 520
;
13s = 520
:
s = 520/13
:
s = 40 mph is the speed of the car
:
60 mph is the speed of the train
:
:
Check:
13*40 = 520
8&2/3 * 60 = 520 mi also