SOLUTION: A semi- truck travels 360 miles through flatline in the same amount of time it travels 180 miles through the mountains. The rate of the truck is 25 miles per hour slower in the mou

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Question 363327: A semi- truck travels 360 miles through flatline in the same amount of time it travels 180 miles through the mountains. The rate of the truck is 25 miles per hour slower in the mountains than in the flatland. Find both the flatline rate and mountain rate.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A semi-truck travels 360 miles through flatland in the same amount of time
it travels 180 miles through the mountains.
The rate of the truck is 25 miles per hour slower in the mountains than in the flatland.
Find both the flatland rate and mountain rate.
:
Let r = the slow rate through the mountains
then
(r+25) = the faster rate through flat areas
:
Write a time equation; time = dist/rate
:
Flat time = Mountain time
360%2F%28%28r%2B25%29%29 = 180%2Fr
Cross multiply
360r = 180(r+25)
360r = 180r + 4500
360r - 180r = 4500
180r = 4500
r = 4500/180
r = 25 mph through the mountains
then
25 + 25 = 50 mph on the flat
:
:
Check solution by finding the actual times, they should be equal
360/50 = 7.2 hrs
180/25 = 7.2 hrs also