SOLUTION: A train leaves New Orleans at 2:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels 42 mph faster than the first. If the second tr

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A train leaves New Orleans at 2:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels 42 mph faster than the first. If the second tr      Log On

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Question 1017542: A train leaves New Orleans at 2:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels 42 mph faster than the first. If the second train overtakes the first at 6:00 PM, what is the speed of each of the two trains?
Found 2 solutions by lwsshak3, josmiceli:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
A train leaves New Orleans at 2:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels 42 mph faster than the first. If the second train overtakes the first at 6:00 PM, what is the speed of each of the two trains?
let x=speed of slower train
travel time of slower train=6-2=4 hrs
x+42=speed of faster train
distance=speed*travel time(same for both trains)
travel time of faster train=6-4=2 hrs
4x=2(x+42)
4x=2x+84
2x=84
x=42
x+42=84
speed of slower train= 84 mph
speed of faster train=42 mph

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
What is the 1st train's head start in miles?
Let +s+ = the speed of the 1st train in mi/hr
From 2PM to 4PM is 2 hrs
+d%5B1%5D+=+s%2A2+
---------------------
Let +d+ = distance the 2nd train travels until
it overtakes the 1st train
From 4PM to 6PM is 2 hrs
Start time when the 2nd train leaves
---------------------
Equation for 1st train:
(1) +d+-+2s+=+s%2A2+
Equation for 2nd train:
(2) +d+=+%28+s%2B42+%29%2A2+
--------------------
Substitute (2) into (1)
(1) +%28+s%2B42+%29%2A2+-+2s+=+s%2A2+
(1) +2s+%2B+84+-+2s+=+2s+
(1) +2s+=+84+
(1) +s+=+42+
and
+s%2B+42+=+42+%2B+42+
+s+%2B+42+=+84+
------------------
The 1st train's speed is 42 mi/hr
The 2nd train's speed is 84 mi/hr
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check:
(2) +d+=+%28+s%2B42+%29%2A2+
(2) +d+=84%2A2+
(2) +d+=+168+
and
(1) +d+-+2s+=+s%2A2+
(1) +d+-+2%2A42+=+42%2A2+
(1) +d+=+84+%2B+84+
(1) +d+=+168+
OK