document.write( "Question 167934: At 1:30 a plane leaves tuscon for baltimore, a distance of 2240 miles. The plane flies at 280mph. A second plane leaves at 2:15 and is schedules to land in baltimore 15 minutes before the first plane. At what rate must the second air plane travel to arrive on schedule. \n" ); document.write( "

Algebra.Com's Answer #123827 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
The distance, $\"2240\"$ , is the same for both planes
\n" ); document.write( "For 1st plane:
\n" ); document.write( "(1) $\"d+=+r%5B1%5D%2At%5B1%5D\"$
\n" ); document.write( "For 2nd plane:
\n" ); document.write( "(2) $\"d+=+r%5B2%5D%2At%5B2%5D\"$
\n" ); document.write( "(3) $\"r%5B1%5D%2At%5B1%5D+=+r%5B2%5D%2At%5B2%5D\"$
\n" ); document.write( "It is given that $\"r%5B1%5D+=+280\"$ mi/hr
\n" ); document.write( "From (1)
\n" ); document.write( "(1) $\"d+=+r%5B1%5D%2At%5B1%5D\"$
\n" ); document.write( " $\"2240+=+280%2At%5B1%5D\"$
\n" ); document.write( " $\"t%5B1%5D+=+8\"$
\n" ); document.write( "The 2nd plane leaves 45 min later and arrives 15 min earlier,
\n" ); document.write( "so it spends 1 hr less in the air than the 1st plane
\n" ); document.write( " $\"t%5B2%5D+=+t%5B1%5D+-+1\"$
\n" ); document.write( "From (3)
\n" ); document.write( " $\"280%2At%5B1%5D+=+r%5B2%5D%2A%28t%5B1%5D+-+1%29\"$
\n" ); document.write( " $\"r%5B2%5D+=+280t%5B1%5D+%2F+%28t%5B1%5D+-+1%29\"$
\n" ); document.write( " $\"r%5B2%5D+=+280%2A8+%2F+%288+-+1%29\"$
\n" ); document.write( " $\"r%5B2%5D+=+2240+%2F+7\"$
\n" ); document.write( " $\"r%5B2%5D+=+320\"$ mi/hr
\n" ); document.write( "check answer:
\n" ); document.write( "(3) $\"r%5B1%5D%2At%5B1%5D+=+r%5B2%5D%2At%5B2%5D\"$
\n" ); document.write( " $\"280%2A8+=+320%2A7\"$
\n" ); document.write( " $\"2240+=+2240\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );