document.write( "Question 161592: 1. find three consecutive even integers whose sum is 42.
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document.write( "2. the difference of the squares of the digits of a two digit positive number is
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document.write( " 27. If the digits are reversed in order and the resulting number is subtracted
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document.write( " from the original number, the difference is also 27.what is the original
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document.write( " number?
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document.write( "3.A's rate of doing work is three times of B. On a given day, A & B work together
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document.write( " for 4 hrs.;B is called away and S finishes the rest of the job in 2 hrs. How
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document.write( " long would it take B to do the complete job alone?
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document.write( "4.Peter can run around a 400m tract in 65 sec. How long does it take for John to
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document.write( " run the 400m if he meets Peter in 35 sec.After they start together in a race
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document.write( " around the tract in opposite direction? \n" );
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Algebra.Com's Answer #119143 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! 1. find three consecutive even integers whose sum is 42. \n" ); document.write( ": \n" ); document.write( "x + (x+2) + (x+4) = 42 \n" ); document.write( "3x + 6 = 42 \n" ); document.write( "3x = 42 - y \n" ); document.write( "3x = 36 \n" ); document.write( "x = 12 \n" ); document.write( ": \n" ); document.write( "; \n" ); document.write( "2. The difference of the squares of the digits of a two digit positive number \n" ); document.write( " is 27. If the digits are reversed in order and the resulting number is \n" ); document.write( " subtracted from the original number, the difference is also 27. \n" ); document.write( " what is the original number? \n" ); document.write( ": \n" ); document.write( "Let the number = 10x + y \n" ); document.write( ": \n" ); document.write( "\"The difference of the squares of the digits of a two digit positive number \n" ); document.write( " is 27. \n" ); document.write( "y^2 - x^2 = 27 \n" ); document.write( "; \n" ); document.write( "\"If the digits are reversed in order and the resulting number is \n" ); document.write( " subtracted from the original number, the difference is also 27.\" \n" ); document.write( ": \n" ); document.write( "10y + x - (10x + y) = 27 \n" ); document.write( "10y + x - 10x - y = 27 \n" ); document.write( "10y - y - 10 + x = 27 \n" ); document.write( "9y - 9x = 27 \n" ); document.write( "Simplify, divide equation by 9 \n" ); document.write( "y - x = 3 \n" ); document.write( "y = (x + 3) \n" ); document.write( "; \n" ); document.write( "Substitute this for y in the 1st equation, find x \n" ); document.write( "(x+3)^2 - x^2 = 27 \n" ); document.write( "(x^2 + 6x + 9) - x^2 = 27 \n" ); document.write( "x^2 - x^2 + 6x + 9 = 27 \n" ); document.write( "6x = 27 - 9 \n" ); document.write( "6x = 18 \n" ); document.write( "x = 3 \n" ); document.write( "Then \n" ); document.write( "y = 3 + 3 \n" ); document.write( "y = 6 \n" ); document.write( "; \n" ); document.write( "Our number is 36; Check it: 63 - 36 = 27 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "3. A's rate of doing work is three times of B. On a given day, A & B work \n" ); document.write( " together for 4 hrs; B is called away and S finishes the rest of the job \n" ); document.write( " in 2 hrs. How long would it take B to do the complete job alone? \n" ); document.write( ": \n" ); document.write( "Where did S come from (a relative perhaps?) I assume you mean A. \n" ); document.write( ": \n" ); document.write( "Let x = time required by A to do the job alone \n" ); document.write( "Then \n" ); document.write( "Let 3x = time required for B to do the job alone. (works 1/3 as fast as A) \n" ); document.write( ": \n" ); document.write( "Let the completed job = 1 \n" ); document.write( ": \n" ); document.write( "The given information tells that A worked 6 hrs, and B worked 4 hrs: \n" ); document.write( ": \n" ); document.write( " \n" ); document.write( "Multiply equation by 3x, results \n" ); document.write( "3(6) + 4 = 3x \n" ); document.write( "18 + 4 = 3x \n" ); document.write( "22 = 3x \n" ); document.write( "x = \n" ); document.write( "x = 7 \n" ); document.write( "then \n" ); document.write( "3(7 \n" ); document.write( ": \n" ); document.write( "Check solution on Calc: 6/7.33 + 4/22 = 1.000; confirms our solution \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "4.Peter can run around a 400m tract in 65 sec. How long does it take for John \n" ); document.write( " to run the 400m if he meets Peter in 35 sec. After they start together in a \n" ); document.write( " race around the tract in opposite direction? ? \n" ); document.write( ": \n" ); document.write( "When they meet, they will have traveled a total of 400 meters in 35 seconds \n" ); document.write( ": \n" ); document.write( "Find Peter's speed in meters/sec: \n" ); document.write( ": \n" ); document.write( "Let s = John's speed in m/sec \n" ); document.write( ": \n" ); document.write( "Write a dist equation; Dist = time * speed \n" ); document.write( ": \n" ); document.write( "35s + 35(6.154) = 400 \n" ); document.write( ": \n" ); document.write( "35s + 215.39 = 400 \n" ); document.write( ": \n" ); document.write( "35s = 400 - 215.39 \n" ); document.write( ": \n" ); document.write( "35s = 184.61 \n" ); document.write( "s = \n" ); document.write( "s = 5.275 m/sec is John's speed \n" ); document.write( ": \n" ); document.write( "Find time for John to run 400 m: \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check solution: \n" ); document.write( "35 * 5.275 = 184.625 m \n" ); document.write( "35 * 6.154 = 215.39 \n" ); document.write( "------------------ \n" ); document.write( "Total dist = 400.0 \n" ); document.write( ": \n" ); document.write( "Do you have any questions about these? \n" ); document.write( " |