document.write( "Question 147094: Brian and Jake left their homes, which are 500 miles apart, and drove straight toward each other. It took 4 hours for the two to meet. If Jake's speed was 15 mph slower than Brian's speed, what was Brian's speed? \n" ); document.write( "
Algebra.Com's Answer #107432 by nerdybill(7384)![]() ![]() You can put this solution on YOUR website! Brian and Jake left their homes, which are 500 miles apart, and drove straight toward each other. It took 4 hours for the two to meet. If Jake's speed was 15 mph slower than Brian's speed, what was Brian's speed? \n" ); document.write( ". \n" ); document.write( "Use D = RT \n" ); document.write( "where \n" ); document.write( "D = distance \n" ); document.write( "R = rate (mph) \n" ); document.write( "T = time (hours) \n" ); document.write( ". \n" ); document.write( "Let x = Brian's speed \n" ); document.write( "then \n" ); document.write( "x-3 = Jake's speed \n" ); document.write( ". \n" ); document.write( "The idea is that the combined \"distance\" traveled by Brian and Jake should be 500 miles. \n" ); document.write( "distance Brian traveled = RT = 4x \n" ); document.write( "distance Jake traveled = RT = 4(x-3) \n" ); document.write( ". \n" ); document.write( "\"distance Brian traveled\" + \"distance Jake traveled\" = 500 \n" ); document.write( "4x + 4(x-3) = 500 \n" ); document.write( "4x + 4x - 12 = 500 \n" ); document.write( "8x = 512 \n" ); document.write( "x = 64 mph (Brian's speed) \n" ); document.write( "x-3 = 64-3 = 61 mph (Jake's speed)\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |