document.write( "Question 561355: A contractor estimated that one of his two bricklayers would take 9 hours to build a certain wall and the other 10 hours. However, he knew from experience that when they worked together, 10 fewer bricks got laid per hour. Since he was in a hurry, he put both men on the job and found it took exactly 5 hours to build the wall. How many bricks did it contain? \n" ); document.write( "
Algebra.Com's Answer #364297 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A contractor estimated that one of his two bricklayers would take 9 hours to build a certain wall and the other 10 hours. \n" ); document.write( "However, he knew from experience that when they worked together, 10 fewer bricks got laid per hour. \n" ); document.write( "Since he was in a hurry, he put both men on the job and found it took exactly 5 hours to build the wall. \n" ); document.write( " How many bricks did it contain? \n" ); document.write( ": \n" ); document.write( "let b = no. of bricks in the wall \n" ); document.write( "then \n" ); document.write( " \n" ); document.write( "and \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "In 5 hrs, 50 less bricks were laid when they worked together \n" ); document.write( ": \n" ); document.write( "b = 5* \n" ); document.write( "b = \n" ); document.write( "multiply by 90 to get rid of the denominators \n" ); document.write( "90b = 9(5b) + 10(5b) - 90(50) \n" ); document.write( "90b = 45b + 50b - 4500 \n" ); document.write( "90b = 95b - 4500 \n" ); document.write( "4500 = 95b - 90b \n" ); document.write( "4500 = 5b \n" ); document.write( "b = 4500/5 \n" ); document.write( "b = 900 bricks in the wall \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "See if that checks out: \n" ); document.write( "900/9 = 100 per hr \n" ); document.write( "900/10 = 90 per hr \n" ); document.write( "5(100) + 5(90) = 950 bricks, but they lay 5(10) less if working together, hence 900 bricks \n" ); document.write( " |