SOLUTION: two trains depart from a station, traveling in opposite directions. the train that departs at 6:30 AM travels 15 km/h faster than the train that departs at 6 AM. At 7 AM they are 1

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Question 221967: two trains depart from a station, traveling in opposite directions. the train that departs at 6:30 AM travels 15 km/h faster than the train that departs at 6 AM. At 7 AM they are 135 km apart. Determine the rate of each train.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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two trains depart from a station, traveling in opposite directions.
the train that departs at 6:30 AM travels 15 km/h faster than the train that
departs at 6 AM. At 7 AM they are 135 km apart.
Determine the rate of each train.
:
Let s = speed of the train that departs at 6 AM
then
(s+15) = speed of the train that departs at 6:30
:
At 7 AM:
the 1st train travel time is 1 hr
the 2nd train travel time is .5 hr
:
Write a distance equation: Dist = time * speed
:
1s + .5(s+15) = 135
1s + .5s + 7.5 = 135
1s + .5s = 135 - 7.5
1.5s = 127.5
s = 127.5%2F1.5
s = 85 mph is the speed of the 6 AM train
:
85 + 15 = 100 mph is the speed of the 6:30 train
;
;
Check solution in the distance equation
1*85 + .5*100 =
85 + 50 = 135