Question 1056978: Elsa drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 10 hours. When Elsa drove home, there was no traffic and the trip only took 7 hours. If her average rate was 18 mph faster on the trip home, how far away does Elsa live from the mountains?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Elsa drove to the mountains last weekend.
There was heavy traffic on the way there, and the trip took 10 hours.
When Elsa drove home, there was no traffic and the trip only took 7 hours.
If her average rate was 18 mph faster on the trip home, how far away does Elsa live from the mountains?
:
Let s = the speed in heavy traffic
then
(s+18) = normal speed
:
Distance is the same each way, write a dist equation; dist = speed * time
10s = 7(s+18)
10s = 7s + 126
10s - 7s = 126
3s = 126
s = 126/3
s = 42 mph in heavy traffic and obviously 60 mph on the return
:
Find the distance
10*42 = 420 mi
check the distance
7*60 = 420 mi
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