document.write( "Question 648179: At 10:30 am two planes leave Houston, one flying east at 560 km/h and the other flying west at 640 km/h. At what time will they be 2100 km apart? \n" ); document.write( "

Algebra.Com's Answer #406589 by josmiceli(19441) $\"\"$ $\"About$

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Just think of one plane as standing still and
\n" ); document.write( "the other moving away at the sum of their speeds.
\n" ); document.write( " $\"+2100+=+%28+560+%2B+640+%29%2At+\"$
\n" ); document.write( " $\"+t+=+2100+%2F+1200+\"$
\n" ); document.write( " $\"+t+=+1.75+\"$ hrs
\n" ); document.write( " $\"+.75+\"$ hr = 45 min
\n" ); document.write( "10:30 + 1:45 = 12:15
\n" ); document.write( "They will be 2100 km at 12:15 PM
\n" ); document.write( "check answer:
\n" ); document.write( "plane #1
\n" ); document.write( " $\"+d%5B1%5D+=+560%2A1.75+\"$
\n" ); document.write( " $\"+d%5B1%5D+=+980+\"$
\n" ); document.write( "plane #2
\n" ); document.write( " $\"+d%5B2%5D+=+640%2A1.75+\"$
\n" ); document.write( " $\"+d%5B2%5D+=+1120+\"$
\n" ); document.write( " $\"+d%5B1%5D+%2B+d%5B2%5D+=+980+%2B+1120+\"$
\n" ); document.write( " $\"+980+%2B+1120+=+2100+\"$
\n" ); document.write( "OK \n" ); document.write( "

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