SOLUTION: An airline leaves Phoenix traveling at an average rate of 420 mph. Thirty minutes later, a second airliner leaves phoenix traveling along a parallel route. If the second plane over

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Question 373857: An airline leaves Phoenix traveling at an average rate of 420 mph. Thirty minutes later, a second airliner leaves phoenix traveling along a parallel route. If the second plane overtakes the first at a point 1680 miles from phoenix, find its rate. The difference in times is 30 min.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Both planes have traveled the same distance when they meet
which is 1680 mi
given:
1st plane:
d+=+r%2At
(1) 1680+=+420%2At
2nd plane:
1680+=+r%2A%28t+-.5%29
(2) 1680+=+r%2At+-+.5r
From (1):
t+=+1680%2F420
t+=+4
(2) 1680+=+4r+-+.5r
r%2A%284+-+.5%29+=+1680
r+=+%282%2F7%29%2A1680
r+=+480
The 2nd plane's rate is 480 mi/hr