SOLUTION: Please help me with this problem: A small airplane flies 810 miles from Los Angeles to Portland, Oregon, with an average speed of 270 miles per hour. An hour and a half after the p

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Question 903836: Please help me with this problem: A small airplane flies 810 miles from Los Angeles to Portland, Oregon, with an average speed of 270 miles per hour. An hour and a half after the plane leaves, a Boeing 747 leaves Los Angeles for Portland. Both planes arrive in Portland at the same time. What was the average speed of the 747?
Found 2 solutions by josmiceli, richwmiller:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
How much of a head start does the small
plane get?
+d%5B1%5D+=+270%2A1.5+
+d%5B1%5D+=+405+
-------------------
Start a stop watch when the 747 leaves
Let +t+ = the time on the stop watch
when both planes arrive in Portland
+810+ mi = the distance the 747 travels
during time +t+
Let +s+ = average speed of the 747
-------------------
747's equation:
(1) +810+=+s%2At+
Small plane's equation:
+810+-+405+=+270t+
(2) +405+=+270t+
-------------------
(2) +t+=+1.5+
and
(1) +810+=+s%2At+
(1) +s+=+810+%2F+1.5+
(1) +s+=+540+
The average speed of the 747 is 540 mi/hr



Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
270t=810
1.5s=810
s=540., t=3