Question

Dale drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took hours. When Dale drove home, there was no traffic and the trip only took hours. If his average rate was miles per hour faster on the trip home, how far away does Dale live from the mountains?

Answer 1

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:

Dale live 315 miles from the mountains

Step-by-step explanation:

Let y be the speed  of Dale to the mountains

Time taken by Dale to the mountains=7 hrs

Therefore distance covered by dale to the mountain = speed × time = 7y ......eqn 1

Time taken by Dale back home = 5hours

Since it speed increased by 18 miles per hour back home it speed = y+18

So distance traveled home =speed × time = (y+18)5 ...... eqn 2

Since distance cover is same in both the eqn 1 and eqn 2.

Eqn 1 = eqn 2

7y = (y+18)5

7y = 5y + 90

7y - 5y = 90 (collection like terms)

2y = 90

Y = 45

Substitute for y in eqn 1 to get distance away from mountain

= 7y eqn 1

= 7×45

= 315 miles.

∴ Dale leave 315 miles from the mountains