SOLUTION: Two planes just took off from Boston, MA. The first plane İs traveling 3.5 times as fast as the second plane. After traveling in the same direction for 5 hours, they are 1312.5 mi

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Question 1188390: Two planes just took off from Boston, MA. The first plane İs traveling 3.5 times as fast as the second plane. After traveling in the same direction for 5 hours, they are 1312.5 miles apart. What is the average speed of each plane? (Hint: Since they are traveling in the same direction, the distance between them will be the difference of their distances.)
Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52848) About Me  (Show Source):
You can put this solution on YOUR website!
.
Two planes just took off from Boston, MA. The first plane is traveling 3.5 times as fast
as the second plane. After traveling in the same direction for 5 hours, they are 1312.5 miles apart.
What is the average speed of each plane?
~~~~~~~~~~~~~~~~ 

Let x be the rate of the second plane; then the rate of the first plane is 3.5 x.


The distance equation between the planes is


    3.5x*5 - 5x = 1312.5

    2.5*(5x)    = 1312.5

     x    = 1312.5/(2.5*5) = 105 miles per hour.


ANSWER.  The second plane speed is 105 mph.

         The first plane speed is  3.5*105 = 367.5 mph.

Solved.



Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Two planes just took off from Boston, MA. The first plane İs traveling 3.5 times as fast as the second plane. After traveling in the same direction for 5 hours, they are 1312.5 miles apart. What is the average speed of each plane?
(Hint: Since they are traveling in the same direction, the distance between them will be the difference of their distances.)
-------------------------
f = the speed of the fastest plane
s = the speed of the slower plane
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f = 3.5s
----
The separation in 5 hours = 5*(f-s) = 1312.5
f - s = 1312.5/5 = 262.5
3.5s - s = 262.5
s = 262.5/2.5 = 105 mi/hr
f = 367.5 mi/hr
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Hint: We don't need hints.