SOLUTION: A car travels 125 miles in the same time an airplane travels 1515 miles. If the rate of the car is 315 miles per hour less than the rate of the airplane, what is the rate of each?

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Question 534386: A car travels 125 miles in the same time an airplane travels 1515 miles. If the rate of the car is 315 miles per hour less than the rate of the airplane, what is the rate of each? Let r represent the rate of the car. Note: Because the time of travel for the car is equal to the time of travel for the plane we can compare the distance and rate (distance = rate x time).
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let t = the time for each
Let s = the speed of the plane
Car:
(1) +125+=+%28+s+-+315+%29%2At+
Plane:
(2) +1515+=+s%2At+
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(2) +t+=+1515%2Fs+
Substitute (2) into (1)
(1) +125+=+%28+s+-+315+%29%2A%281515%2Fs%29+
(1) +125+=+1515+-+477225%2Fs+
(1) +125s+=+1515s+-+477225+
(1) +1390s+=+477225+
(1) +s+=+343.327+ mi/hr
+s+-+315+=+343.327+-+315+
+s+-+315+=+28.327+ mi/hr
The speed of the car is 28.327 mi/hr
The speed of the plane is 343.327 mi/hr
------------------
check:
(2) +t+=+1515%2F343.327+
(2) +t+=+4.413+ hrs
and
(1) +125+=+%28+343.327+-+315+%29%2A4.413+
(1) +125+=+28.327%2A4.413+
(1) +125+=+125.007+
Seems close enough