document.write( "Question 389844: a car travels 20 km/h faster than a truck. The car covers 360 km in 3 hours less time than the truck. Find the speed of the truck. (Show your solution) \n" ); document.write( "
Algebra.Com's Answer #276374 by ewatrrr(24785)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "Hi,
\n" ); document.write( "Let r and t represent the speed and time for the truck
\n" ); document.write( "Write as we Read*** D = r*t for the truck and car
\n" ); document.write( " r*t = 360km r = 360km/t
\n" ); document.write( "(r+20kmph)(t-3hr) = 360km substituting for r so as to solve for t
\n" ); document.write( " (360/t + 20)(t-3) = 360km
\n" ); document.write( " \"%28360+%2B+20t%29%2Ft%2A%28t-3%29+=+360\"
\n" ); document.write( " \"%28360+%2B+20t%29%2A%28t-3%29+=+360t\"
\n" ); document.write( " 360t + 20t^2 -3*360 -60t = 360t
\n" ); document.write( " 20t^2 -60t - 3*360 = 0
\n" ); document.write( " t^2 -3t - 54 = 0
\n" ); document.write( "factoring
\n" ); document.write( "(t-9)(t+6) = 0 tossing out negative solution
\n" ); document.write( " t = 9hr r = 40kmph for the truck\r
\n" ); document.write( "\n" ); document.write( "CHECKING our Answer for car:
\n" ); document.write( " 60kmph*6hr = 360km
\n" ); document.write( " \n" ); document.write( "
\n" );