document.write( "Question 1029020: An aeroplane flies from A to B at a speed of 750km/h. On the return trip there was a strong tail wind and the airplane flew at 900km/h. The return flight took 20 min less than the original. How many hours did the return trip take? \n" ); document.write( "

Algebra.Com's Answer #644080 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+t+\"$ = the time in hrs going from A to B
\n" ); document.write( " $\"+t+-+1%2F3+\"$ = the time in hrs on return trip
\n" ); document.write( "--------------------
\n" ); document.write( "Equation for A to B
\n" ); document.write( "(1) $\"+d+=+750t+\"$
\n" ); document.write( "Equation for B to A
\n" ); document.write( "(2) $\"+d+=+900%2A%28+t+-+1%2F3+%29+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "By substitution:
\n" ); document.write( "(2) $\"+750t+=+900%2A%28+t+-+1%2F3+%29+\"$
\n" ); document.write( "(2) $\"+750t+=+900t+-+300+\"$
\n" ); document.write( "(2) $\"+150t+=+300+\"$
\n" ); document.write( "(2) $\"+t+=+2+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+t+-+1%2F3+=+2+-+1%2F3+\"$
\n" ); document.write( " $\"+t+-+1%2F3+=+1+%2B+2%2F3+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+%282%2F3%29%2A60+=+40+\"$ min
\n" ); document.write( "The return time is 1 hr and 40 min
\n" ); document.write( "----------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+d+=+750t+\"$
\n" ); document.write( "(1) $\"+d+=+750%2A2+\"$
\n" ); document.write( "(1) $\"+d+=+1500+\"$ km
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+=+900%2A%28+2+-+1%2F3+%29+\"$
\n" ); document.write( "(2) $\"+d+=+900%2A%285%2F3%29+\"$
\n" ); document.write( "(2) $\"+d+=+1500+\"$ km
\n" ); document.write( "OK \n" ); document.write( "

\n" );