Two trains leave a train station at the same time. One travels north at 9 miles per hour. The other train travels south at 11 miles per hour. In how many hours will the two trains be 92 miles apart?
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Two trains leave a train station at the same time.
One travels north at 9 miles per hour.
The other train travels south at 11 miles per hour.
In 4.6 hours the two trains will be 92 miles apart.
Anonymous
distance = rate * time
Let t = time traveled
Both trains are traveling in the same amount of time. Since they both leave at the same time in opposite directions the total distance travelled between them has to be 92.
9t + 11t = 92
20t = 92
t = 92/20 = 4.6
4.6 hours is the answer.
Como
Relative speed is 20 mph
time = 92 / 20 = 4 • 6 hours = 4 h 36 min
Anonymous
Their combined speed is (9 + 11 = 20 mph). Therefore every hour their combined distance apart is 20 miles.
Time = Distance/Speed
= 92/20
= 4 12/20
= 4 3/5 hours
= 4 hours 36 minutes
marys.momma
As our Algebra I teacher always used to say, "What equals what?"
By this he meant, "Set up your equation(s) in mathematical terms, to describe the situation."
It seems to me that for every hour that passes, the trains get twenty miles further apart.
Plug and chug.