document.write( "Question 206592: I know rate times time equals distance, but I'm still confused. Steve traveled 200 miles at a certain speed. Had he gone 10mph faster, the trip would have taken 1 hour less. Find the speed of his vehicle. \n" ); document.write( "
Algebra.Com's Answer #156129 by Theo(13342)![]() ![]() You can put this solution on YOUR website! Steve traveled 200 miles at a certain speed. Had he gone 10mph faster, the trip would have taken 1 hour less. Find the speed of his vehicle. \n" ); document.write( "----- \n" ); document.write( "let x = the certain speed in miles per hour. \n" ); document.write( "let h = the time it took in hours. \n" ); document.write( "----- \n" ); document.write( "rate * time = distance becomes x * h = 200 \n" ); document.write( "----- \n" ); document.write( "if he had gone 10 mph faster his rate would have been 10 mph more than whaqt it was which is the same as x + 10 \n" ); document.write( "----- \n" ); document.write( "if he had gone 10 mph faster his time would have been 1 hour less which is the same as h - 1 \n" ); document.write( "----- \n" ); document.write( "solve for x \n" ); document.write( "----- \n" ); document.write( "you have 2 equations. \n" ); document.write( "----- \n" ); document.write( "the first equation is x * h = 200 \n" ); document.write( "the second equation is (x+10)*(h-1) = 200 \n" ); document.write( "----- \n" ); document.write( "since both equations are equal to 200 then they are equal to each other. \n" ); document.write( "----- \n" ); document.write( "your equation becomes: \n" ); document.write( "x*h = (x+10)*(h-1) \n" ); document.write( "----- \n" ); document.write( "if you multiply this out you get h^2 - h - 20 = 0 which factors out to be (h-5) * (h+4) = 0 which makes h = 5 or h = -4. \n" ); document.write( "----- \n" ); document.write( "since h = -4 is not possible your answer has to be be h = 5 \n" ); document.write( "----- \n" ); document.write( "if you substitute 5 for h in your first equation you get 5x = 200 which makes x = 40 \n" ); document.write( "----- \n" ); document.write( "your answer should be: \n" ); document.write( "x = 40 = speed he traveled at. \n" ); document.write( "h = 5 = number of hours it took. \n" ); document.write( "----- \n" ); document.write( "5*40 = 200 so this part checks out. \n" ); document.write( "----- \n" ); document.write( "second part states if he went 10 mph faster he would have taken 1 hour less. \n" ); document.write( "----- \n" ); document.write( "10 mph faster would be 50 mph. \n" ); document.write( "1 hour less would be 4 hours. \n" ); document.write( "50 * 4 = 200 so this part checks out also. \n" ); document.write( "----- \n" ); document.write( "answer is his original rate of travel was 40 miles per hour and the original time it took was 5 hours. \n" ); document.write( "----- \n" ); document.write( " |