document.write( "Question 826091: Kimberly took three hours to drive to her friends home on the weekend. Her average speed was 85 km/h for the first two hours. What was her average speed for the last hour of the trip if her average speed was 75 km/h for the whole trip? \n" ); document.write( "
Algebra.Com's Answer #497901 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
Kimberly took three hours to drive to her friends home on the weekend.
\n" ); document.write( " Her average speed was 85 km/h for the first two hours.
\n" ); document.write( " What was her average speed for the last hour of the trip if her average speed was 75 km/h for the whole trip?
\n" ); document.write( ":
\n" ); document.write( "Let s = the speed on the last hour of the trip
\n" ); document.write( ":
\n" ); document.write( "Write a distance equation, dist = time * speed
\n" ); document.write( ":
\n" ); document.write( "dist 1st 2 hr + dist last hr = total dist
\n" ); document.write( "2(85) + 1s = 3(75)
\n" ); document.write( "190 + s = 225
\n" ); document.write( "s = 225 - 190
\n" ); document.write( "s = 35 km/h for the last hour
\n" ); document.write( "
\n" );