document.write( "Question 1132115: On an automobile trip,Jessa maintained a steady speed for 30 mins. Rush hour traffic slowed her speed by 40 kph for the last part of the trip.The entire trip, a distance of 38km took 1 hour and 15 mins. What was her speed during the first part of the trip? (use only one variable)(thanks in advance) \n" ); document.write( "

Algebra.Com's Answer #749015 by ikleyn(52798) $\"\"$ $\"About$

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

\r\n" );
document.write( "The total time is  1 hour 15 minutes = 1.25 hours.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The first part of the trip at high speed took 30 minutes = 0.5 of an hour.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Hence, the second part of the trip took  1.25 - 0.5 = 0.75 of an hour.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Let x be the speed during the first part of the trip (the value under the question).\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Then the first part of the trip was  0.5*x kilometers long (time multiplied by the speed).\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The second part of the trip was  0.75*(x-40)  kilometers long.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Together, these two parts are the entire distance of 38 kilometers.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It gives you an equation\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    0.5x + 0.75*(x-40) = 38   kilometers.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Simplify and solve for x:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    0.5x + 0.75x - 30 = 38\r\n" );
document.write( "\r\n" );
document.write( "    1.25x = 30 + 38 = 68.\r\n" );
document.write( "\r\n" );
document.write( "    x =  = 54.4 kilometers per hour.     ANSWER\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( "See introductory lessons on Travel and Distance problems\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" );