document.write( "Question 137153: a 555-mile, 5-hour plane trip was flown at two speeds. For the first part of the trip, the average speed was 105 mph. Then the tailwind picked up, and the remainder of the trip was flown at an average speed of 155 mph. For how long did the plane fly at each speed? \n" ); document.write( "

Algebra.Com's Answer #100352 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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a 555-mile, 5-hour plane trip was flown at two speeds. For the first part of the trip, the average speed was 105 mph. Then the tailwind picked up, and the remainder of the trip was flown at an average speed of 155 mph. For how long did the plane fly at each speed?
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\n" ); document.write( "Let t = time flown at 155 mph
\n" ); document.write( "Total time was 5 hrs,therefore:
\n" ); document.write( "(5-t) = time flown at 105
\n" ); document.write( ":
\n" ); document.write( "Write a distance equation: dist = speed * time
\n" ); document.write( ":
\n" ); document.write( "Fast speed dist = slow speed dist = 555 mi
\n" ); document.write( "155t + 105(5-t) = 555
\n" ); document.write( ":
\n" ); document.write( "155t + 525 - 105t = 555
\n" ); document.write( ":
\n" ); document.write( "155t - 105t = 555 - 525
\n" ); document.write( ":
\n" ); document.write( "50t = 30
\n" ); document.write( "t = $\"30%2F50\"$
\n" ); document.write( "t = .6 hrs at 155 mph
\n" ); document.write( ":
\n" ); document.write( "5 - .6 = 4.4 hrs at 105 mph
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\n" ); document.write( ":
\n" ); document.write( "Check solution by finding the total miles at both speed:
\n" ); document.write( "105(4.4) + 155(.6) =
\n" ); document.write( "462 + 93 = 555 mi; confirms our solutions \n" ); document.write( "

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