document.write( "Question 1069037: Two planes, which are 2920 miles apart, fly toward each other. Their speeds differ by 80 mph. If they pass each other in 4 hours, what is the speed of each? \n" ); document.write( "

Algebra.Com's Answer #684274 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
In this type of problem, you can think of one of
\n" ); document.write( "the planes as standing still, and the other one
\n" ); document.write( "flying at the sum of their speeds
\n" ); document.write( "-------------------------------
\n" ); document.write( "Let $\"+s+\"$ = the speed in mi/hr of the slower plane
\n" ); document.write( " $\"+2920+=+%28+s+%2B+s+%2B+80+%29%2A4+\"$
\n" ); document.write( " $\"+2920+=+%28+2s+%2B+80+%29%2A4+\"$
\n" ); document.write( " $\"+2920+=+8s+%2B+320+\"$
\n" ); document.write( " $\"+8s+=+2920+-+320+\"$
\n" ); document.write( " $\"+8s+=+2600+\"$
\n" ); document.write( " $\"+s+=+325+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+s+%2B+80+=+405+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "Their speeds are
\n" ); document.write( "325 mi/hr and 405 mi/hr
\n" ); document.write( "-----------------------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+d%5B1%5D+=+325%2A4+\"$
\n" ); document.write( " $\"+d%5B1%5D+=+1300+\"$ mi
\n" ); document.write( "and
\n" ); document.write( " $\"+d%5B2%5D+=+405%2A4+\"$
\n" ); document.write( " $\"+d%5B2%5D+=+1620+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+d%5B1%5D+%2B+d%5B2%5D+=+1300+%2B+1620+\"$
\n" ); document.write( " $\"+d%5B1%5D+%2B+d%5B2%5D++=+2920+\"$
\n" ); document.write( "OK \n" ); document.write( "

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