SOLUTION: Hello. I could really use some help on this word problem. If I could set up the equation I could solve it but I am having trouble. Please help. Trains A and B are traveling in t

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Hello. I could really use some help on this word problem. If I could set up the equation I could solve it but I am having trouble. Please help. Trains A and B are traveling in t      Log On

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Question 602068: Hello. I could really use some help on this word problem. If I could set up the equation I could solve it but I am having trouble. Please help.
Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 80 mph and train B is traveling at 90 mph. Train A passes a station at 9:20 P.M. If train B passes the same station at 9:32 P.M., what time will train B catch up to train A?

Found 2 solutions by josmiceli, scott8148:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
How much of a head start does train A have? The
head start is from 9:20 to 9:32, which is 12 minutes.
In 12 minutes, train A travels
+80%2A%2812%2F60%29+=+80%2F5+
+80%2F5+=+16+ miles ( note that 12 min is 12/60 hours )
--------------------
Now start a stopwatch when train B leaves the station.
Both trains will travel for the same amount of time
until they meet.
Let the time until they meet = +t+ hours
Let the distance that train B has to travel = +d+
--------------------
Equation for A:
(1) +d+-+16+=+80t+
Equation for B:
(2) +d+=+90t+
--------------
Substitute (2) into (1)
(1) +90t+-+16+=+80t+
(1) +10t+=+16+
(1) +t+=+1.6+ hrs
+.6%2A60+=+36+ minutes
B will catch up to A 1 hour and 36 minutes after
9:32, which is 11:08 PM


Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
A has a 12 min lead on B ___ 12 min is 1/5 hr (12/60)

A is traveling 80 mph, so 1/5 hr is 16 mi (80 * 1/5)

B is catching A at 10 mph (90 - 80)

it will take B 1.6 hr to catch A (16 / 10) ___ this is from the time that B passes the station

equation-wise; the distances are equal when B catches up, and A has 1/5 hr head start

90t = 80(t + 1/5)

the question asks what time, so t must be added to 9:32 PM