document.write( "Question 937584: A new automatic machine can do a job in 1 hour less than an older machine. Together they can do the same job in 1.2 hours. How long would it take each machine to do the job alone? \n" ); document.write( "
Algebra.Com's Answer #571024 by TimothyLamb(4379)![]() ![]() You can put this solution on YOUR website! x = time for old machine \n" ); document.write( "y = time for new machine \n" ); document.write( "--- \n" ); document.write( "y = x - 1 \n" ); document.write( "--- \n" ); document.write( "r = w/t \n" ); document.write( "rates are additive: \n" ); document.write( "r = 1/x + 1/y \n" ); document.write( "t = w/r \n" ); document.write( "t = 1/(1/x + 1/y) \n" ); document.write( "1.2 = 1/(1/x + 1/y) \n" ); document.write( "1.2(1/x + 1/y) = 1 \n" ); document.write( "1.2/x + 1.2/y = 1 \n" ); document.write( "1.2y/xy + 1.2x/xy = 1 \n" ); document.write( "1.2y + 1.2x = xy \n" ); document.write( "1.2(y + x) = xy \n" ); document.write( "--- \n" ); document.write( "substitute y = x - 1 \n" ); document.write( "--- \n" ); document.write( "1.2(x - 1 + x) = x(x - 1) \n" ); document.write( "1.2(2x - 1) = xx - x \n" ); document.write( "2.4x - 1.2 = xx - x \n" ); document.write( "xx - x - 2.4x + 1.2 = 0 \n" ); document.write( "xx - 3.4x + 1.2 = 0 \n" ); document.write( "--- \n" ); document.write( "the above quadratic equation is in standard form, with a=1, b=-3.4 and c=1.2 \n" ); document.write( "--- \n" ); document.write( "to solve the quadratic equation, by using the quadratic formula, copy and paste this: \n" ); document.write( "1 -3.4 1.2 \n" ); document.write( "into this solver: https://sooeet.com/math/quadratic-equation-solver.php \n" ); document.write( "--- \n" ); document.write( "the quadratic has two real roots at: \n" ); document.write( "--- \n" ); document.write( "x = 3 \n" ); document.write( "x = 0.4 \n" ); document.write( "--- \n" ); document.write( "the root x=0.4 makes y negative and doesn't fit the problem statement, so use the root x=3: \n" ); document.write( "--- \n" ); document.write( "x = 3 \n" ); document.write( "y = x - 1 \n" ); document.write( "y = 2 \n" ); document.write( "--- \n" ); document.write( "answer: \n" ); document.write( "x = time for old machine = 3 hours \n" ); document.write( "x = time for new machine = 2 hours \n" ); document.write( "--- \n" ); document.write( "Free algebra tutoring live chat: \n" ); document.write( "https://sooeet.com/chat.php?gn=algebra \n" ); document.write( "--- \n" ); document.write( "Solve and graph linear equations: \n" ); document.write( "https://sooeet.com/math/linear-equation-solver.php \n" ); document.write( "--- \n" ); document.write( "Solve quadratic equations with quadratic formula: \n" ); document.write( "https://sooeet.com/math/quadratic-formula-solver.php \n" ); document.write( "--- \n" ); document.write( "Solve systems of linear equations up to 6-equations 6-variables: \n" ); document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php \n" ); document.write( "--- \n" ); document.write( " |