document.write( "Question 1027769: Mr. John traveled to a city 120 miles from his home to attend a meeting. Due to car trouble, his average speed returning was 12 mph less than his speed going. If the total time for the round trip was 4 hours, at what rate of speed did he travel to the city? (Round your answer to the nearest tenth.) \n" ); document.write( "

Algebra.Com's Answer #642969 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+t+\"$ = his time in hours going to the meeting
\n" ); document.write( "Let $\"+s+\"$ = his speed in mi/hr going to the meeting
\n" ); document.write( "---------------------
\n" ); document.write( "Equation for going to the meeting
\n" ); document.write( "(1) $\"+120+=+s%2At+\"$
\n" ); document.write( "Equation for returning from the meeting
\n" ); document.write( "(2) $\"+120+=+%28+s+-+12+%29%2A%28+4+-+t+%29+\"$
\n" ); document.write( "----------------------------
\n" ); document.write( "(1) $\"+t+=+120%2Fs+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+120+=+4s+-+48+-+s%2At+%2B+12t+\"$
\n" ); document.write( "(2) $\"+120+=+4s+-+48+%2B+t%2A%28+12+-+s+%29+\"$
\n" ); document.write( "(2) $\"+120+=+4s+-+48+%2B+%28+120%2Fs+%29%2A%28+12+-+s+%29+\"$
\n" ); document.write( "(2) $\"+120+%2B+48+=+4s+%2B+1440%2Fs+-+120+\"$
\n" ); document.write( "(2) $\"+120+-+48+%2B+120+=+4s+%2B+1440%2Fs%0D%0A%282%29+%7B%7B%7B+288+=+4s+%2B+1440%2Fs+\"$
\n" ); document.write( "(2) $\"+288s+=+4s%5E2+%2B+1440+\"$
\n" ); document.write( "(2) $\"+4s%5E2+-+288s+%2B+1440+=+0+\"$
\n" ); document.write( "(2) $\"+s%5E2+-72s+%2B+360+=+0+\"$
\n" ); document.write( "Complete the square:
\n" ); document.write( "(2) $\"+s%5E2+-72s+%2B+%28+-72%2F2%29%5E2+=+-360+%2B+%28+-72%2F2+%29%5E2+\"$
\n" ); document.write( "(2) $\"+s%5E2+-72s+%2B+1296+=+-360+%2B+1296+\"$
\n" ); document.write( "(2) $\"+s%5E2+-72s+%2B+1296+=+936+\"$
\n" ); document.write( "(2) $\"+%28+s+-+36+%29%5E2+=+30.594%5E2+\"$
\n" ); document.write( "(2) $\"+s+-+36+=+30.594+\"$
\n" ); document.write( "(2) $\"+s+=+30.594+%2B+36+\"$
\n" ); document.write( "(2) $\"+s+=+66.594+\"$
\n" ); document.write( "he traveled at 66.6 mi/hr to the city
\n" ); document.write( "---------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+120+=+s%2At+\"$
\n" ); document.write( "(1) $\"+120+=+66.594t+\"$
\n" ); document.write( "(1) $\"+t+=+1.802+\"$ hrs
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+120+=+%28+s+-+12+%29%2A%28+4+-+t+%29+\"$
\n" ); document.write( "(2) $\"+120+=+%28+66.594+-+12+%29%2A%28+4+-+t+%29+\"$
\n" ); document.write( "(2) $\"+120+=+54.594%2A%28+4+-+t+%29+\"$
\n" ); document.write( "(2) $\"+120+=+218.376+-+54.594t+\"$
\n" ); document.write( "(2) $\"+218.376+-+120+=+54.594t+\"$
\n" ); document.write( "(2) $\"+54.594t+=+98.376+\"$
\n" ); document.write( "(2) $\"+t+=+1.802+\"$ hrs
\n" ); document.write( "OK
\n" ); document.write( "check the math \n" ); document.write( "

\n" );