[email protected] wrote: Train A leaves the station and travels at 30 miles per hour. Three hours later, train Ð’ leaves the same station traveling in the same direction at 40 miles per hour on a parallel track. How far from the station was train A overtaken by train B?
(A) 90
(B) 180
(C) 200
(D) 300
(E) 360
Train A leaves the station and travels at 30 miles per hour...for 3 hours
Train A/s travel distance = (rate)(time) = (30)(3) =
90 miles
So, at the moment, there's a
90 mile gap between the trains
then . . .
train Ð’ leaves the same station traveling in the same direction at 40 miles per hour on a parallel track.
Train B's speed is 10 miles per hour FASTER than Train A's speed.
So, the gap between them SHRINKS at a rate of
10 miles per hour.
We want to know the time it takes for the gap to shrink from
90 miles to 0 miles (a difference of 90 miles).
Time = distance/rate = 90/
10 = 9 hours
How far does train B travel in those 9 hours?
Distance = (rate)(time) = [spoiler](40)(9) = 360 miles = E [/spoiler]
Cheers,
Brent
