SOLUTION: This word problem has driven me crazy for a week. Please help me and show me how you came up with the answer. Trains A and B are traveling in the same direction on parallel trac

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Question 325143: This word problem has driven me crazy for a week. Please help me and show me how you came up with the answer.
Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 40 m.p.h. and Train B is traveling at 50 m.p.h.
Train A passes a station at 6:10 p.m.
If train B passes the same station at 6:40, at what time will Train B catch up to Train A ?

Found 2 solutions by Theo, Alan3354:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
Trains A and B travel in the same direction on different tracks.

Trains A is traveling at 40 mph.
Train B is traveling at 50 mph.

Train A passes a station at 6:10 pm.
Train B passes the same station at 6:40 pm.

When will train B catch up with train A.

This is a rate * time = distance type of problem.

The rates will be given.
The distance will be the same for both trains.
The time will be different for both trains as shown below:

Since train A passes the station at 6:10 pm and train B passes the station at 6:40 pm, then train A will have traveled 1/2 hours more than train B.

If we let T = the time that train B travels, then the time that train A travels is T + .5

Formula for train A:

rate * time = distance
rate = 40
time = T + .5
distance = D

Formula for train A becomes:

40 * (T + .5) = D

Formula for train B:

rate * time = distance
rate = 50
time = T
distance = D

Formula for train B becomes:

50 * T = D

You need to solve these two equations simultaneously to get your answer.

The formulas are:

40 * (T + .5) = D
50 * T = D

Simplification of these two equations results in:

40*T + 40*.5 = D
50*T = D

Simplify further to get:

40*T + 20 = D
50*T = D

Subtract the first equation from the second equation to get:
10*T - 20 = 0
Add 20 to both sides of the equation to get:
10*T = 20
Divide both sides of the equation by 10 to get:
T = 2

You now know what T is.

If you substitute 2 for T in both equations you will get:

40*2.5 = D
50*2 = D

Solve for D to get:
40*2.5 = 100
50*2 = 100

D = 100 in both cases as it should.

The question is what time does train B catch up with train A.

Train B has passed the station at 6:40 pm.

Add 2 hours to that and you get 8:40 pm as the time that train B catches up with train A.

Train A has passed the station at 6:10 pm.

Add 2.5 hours to that and you get 8:40 pm as the time that train B catches up with train A.


Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 40 m.p.h. and Train B is traveling at 50 m.p.h.
Train A passes a station at 6:10 p.m.
If train B passes the same station at 6:40, at what time will Train B catch up to Train A ?
-----------------------
In 1/2 hour (640 - 610) train A goes 20 miles (1/2 x 40 mph)
Train B gains on train A at 10 mph (50 - 40)
It takes train B 2 hours to overtake train A (20/10)
6:40 + 2 hours = 8:40