Question

Dale drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 7 hours. When Dale drove home, there was no traffic and the trip only took 5 hours. If his average rate was 18 miles per hour faster on the trip home, how far away does Dale live from the mountains? Do not do any rounding.

Answer 1

Let r and r+18 be Dale's rate with and without traffic, respectively. Then
7r=5(r+18)
2r=90
r=45
7r=315
Dale lives 315 miles from the mountains
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