document.write( "Question 1167511: Amanda leaves Boston at 10:00 AM and drives to Buffalo, NY, which is 400 miles away. After 4 hours, the traffic causes Amanda to reduce her speed by 20 mph. She stops to rest for two hours, and then arrives in Buffalo at 8:00 PM.
\n" ); document.write( "What was Amanda's initial speed?
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #792105 by ikleyn(52779) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "Let \"r\" be the initial speed, in miles per hour.\r\n" );
document.write( "\r\n" );
document.write( "Then the lower speed was (r-20) mph.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The total driving time was 10 hour from 10:00 am to 8:00 pm minus 2 hour for the rest = 8 hours.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Of them, 4 hours she drove at the rate r mph, and the remaining 8 - 4 = 4 driving hours at the lower rate (r-20) mph.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The total distance equation is\r\n" );
document.write( "\r\n" );
document.write( "    4*r + 4*(r-20) = 400\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Simplify and solve\r\n" );
document.write( "\r\n" );
document.write( "    4r + 4r - 80 = 400\r\n" );
document.write( "\r\n" );
document.write( "    8r           = 400 + 80 = 480\r\n" );
document.write( "\r\n" );
document.write( "     r                      = 480/8 = 60 mph.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "ANSWER.  The initial speed / (rate) was 60 mph.\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "----------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "For simple Travel & Distance problems, see introductory lessons \r
\n" ); document.write( "\n" ); document.write( "    - Travel and Distance problems \r
\n" ); document.write( "\n" ); document.write( "    - Travel and Distance problems for two bodies moving in opposite directions \r
\n" ); document.write( "\n" ); document.write( "    - Travel and Distance problems for two bodies moving in the same direction (catching up)\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "They are written specially for you.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "You will find the solutions of many similar problems there.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Read them and learn once and for all from these lessons on how to solve simple Travel and Distance problems.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Become an expert in this area.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );