a semi truck travels 300 miles through the flat land in the same amount of time that it travels?

Question

180 miles throught the mountain. the rate of the truck is 20 miles per hour, slower in the mountains than in the flat land. find both the flat land rate and the mountain rate.

Answer 1

Let the speed of the truck be x miles per hour on flat land and x-20 MPH on the nountains
Therefore,time taken to travel 33 miles on flat land=300/x
and the time taken to travel 180 miles on mountains=180/(x-20)
by the problem.
300/x=180/(x-20)
=>300(x-20)=180x [by cross-multiplication]
=>300x-6000=180x
=>300x-180x=6000
=>120x=6000
=>x=6000/120=50
Therefore the sped of the truck on plains is 50mph and that on the mountains is 50-20 or 30mph

Answer 2

30 MPH in the mountains

50 MPH in the flat lands