Answer: 420 miles away
Step-by-step explanation:
Lashonda drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 10 hours. When Lashonda drove home, there was no traffic and the trip only took 7 hours. If her average rate was 18 miles per hour faster on the trip home, how far away does Lashonda live from the mountains?
one to mountains:
s = x miles
t = 10h
vā = x/10
Back home
s = x miles
t = 7h
vā = x/7
And we know that vā = vā + 18. So, we have:
vā = vā + 18
vā = x/10 ā x = 10vā
vā = x/7 ā x = 7vā
10vā = 7vā ā Ā vā = 7vā/10
vā = vā + 18
vā = 7vā/10 + 18
10vā = 7vā + 180
10vā - 7vā = 180
3vā = 180
vā = 60 mi/h
vā = x/7 ā x = 60.7 = 420 miles
