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)\"\" \"About 
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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( "\"b%2F9\" = no. of bricks laid per hr by the 1st bricklayer
\n" ); document.write( "and
\n" ); document.write( "\"b%2F10\" = no. of brick laid per hr by the 2nd bricklayer
\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*\"b%2F10\" + 5*\"b%2F9\" - 50
\n" ); document.write( "b = \"%285b%29%2F10\" + \"%285b%29%2F9\" - 50
\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
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