SOLUTION: A car travels 400 miles on level terrain in the same amount of time it travels 160 miles on mountainous terrain. If the rate of the car is 30 miles per hour less in the mountains t

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Question 572856: A car travels 400 miles on level terrain in the same amount of time it travels 160 miles on mountainous terrain. If the rate of the car is 30 miles per hour less in the mountains than on level ground, find its rate in the mountains.
Found 3 solutions by solver91311, mananth, jorel555:
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!

Solve for . Hint: Cross-multiply.

John

My calculator said it, I believe it, that settles it

Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website!
Level x mph
Mountain -30 slower x -30 mph

Level 400 miles
Mountain 160 miles
Level time = Mountain time
t=d/r
400 / x = 160 /( x -30 )
cross multiply
400 ( x -30 ) = 160 x
400 x + -12000 = 160 x
400 x - 160 x = 12000
400 x = 12000
/ 360
x = 60 mph SPEED ON LEVEL
speed in mountains = 60-30 = 30 MPH

Answer by jorel555(1290)   (Show Source):
You can put this solution on YOUR website!
400/x=160/x-30
Cross multiply, you get
400(x-30)=160x
400x-12000=160x
400x-160x=12000
240x=12000
x=50
x-30=20
Check your math:
400/50=160/20
8=8!!!!!