document.write( "Question 206942: two technicians can complete a mailing in 3 hours when working together. alone, one can complete the mailing 2 hours faster than the other. how long will it take each person to complete the mailing alone? compute answer to two decimal places. \n" ); document.write( "
Algebra.Com's Answer #156453 by Theo(13342)\"\" \"About 
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let x = rate of first technician
\n" ); document.write( "let y = rate of second technician.
\n" ); document.write( "-----
\n" ); document.write( "working together they can complete a mailing in 3 hours.
\n" ); document.write( "(x + y) * 3 = 1
\n" ); document.write( "(x + y) is their combined rate.
\n" ); document.write( "3 = number of hours
\n" ); document.write( "1 = units produced.
\n" ); document.write( "-----
\n" ); document.write( "they produced 1 unit of mailing in 3 hours working together.
\n" ); document.write( "-----
\n" ); document.write( "let the first technician be the faster mailer.
\n" ); document.write( "the first technician works at a rate of x mailings per hour.
\n" ); document.write( "the second technician works at a rate of y mailings per hour.
\n" ); document.write( "-----
\n" ); document.write( "alone, the first technician can complete the mailing 2 hours faster than the other.
\n" ); document.write( "-----
\n" ); document.write( "let h = amount of time in hours it takes for the first technician to complete the mailing.
\n" ); document.write( "-----
\n" ); document.write( "x * h = 1 mailing
\n" ); document.write( "-----
\n" ); document.write( "since the first technician can complete the mailing in 2 hours less than the second technician, then (h+2) represents the time it takes the second technician to complete the mailing.
\n" ); document.write( "-----
\n" ); document.write( "y * (h+2) = 1 mailing
\n" ); document.write( "-----
\n" ); document.write( "since x * h = 1, then x = (1/h) which looks like \"%281%2Fh%29\"
\n" ); document.write( "-----
\n" ); document.write( "since y * (h+2) = 1, then y = (1/(h+2)) which looks like \"%281%2F%28h%2B2%29%29\"
\n" ); document.write( "-----
\n" ); document.write( "formula of (x+y)*3 = 1 becomes ((1/h) + (1/(h+2))) * 3 = 1
\n" ); document.write( "this looks like \"%28%281%2Fh%29+%2B+%281%2F%28h%2B2%29%29%29+%2A+3+=+1\"
\n" ); document.write( "-----
\n" ); document.write( "multiply both sides of this equation by (h)*(h+2) to get ((h+2) + (h)) * 3 = (h)*(h+2)
\n" ); document.write( "this looks like \"%28%28h%2B2%29+%2B+%28h%29%29+%2A+3+=+%28h%29%2A%28h%2B2%29\"
\n" ); document.write( "-----
\n" ); document.write( "this becomes 6h + 6 = h^2 + 2h which looks like \"6h+%2B+6+=+h%5E2+%2B+2h\"
\n" ); document.write( "-----
\n" ); document.write( "this eventually results in h^2 - 4h - 6 = 0 which looks like \"h%5E2+-+4h+-+6+=+0\"
\n" ); document.write( "-----
\n" ); document.write( "using the quadratic formula, the roots are either:
\n" ); document.write( "h = 5.16227766 or h = -1.16227766
\n" ); document.write( "-----
\n" ); document.write( "since h can't be negative, the only possible answer is h = 5.16227766
\n" ); document.write( "-----
\n" ); document.write( "if h = 5.16227766, then x = 1/5.16227766 = .193712943 and y = 1/7.16227766 = .13962039
\n" ); document.write( "-----
\n" ); document.write( "to test this out, we substitute for x and h in the equations we created that contain h in them.
\n" ); document.write( "-----
\n" ); document.write( "first equation is \"%28%281%2Fh%29+%2B+%281%2F%28h%2B2%29%29%29+%2A+3+=+1\"
\n" ); document.write( "-----
\n" ); document.write( "this becomes \"%28%281%2F5.16227766%29+%2B+%281%2F7.16227766%29%29+%2A+3+=+1\"
\n" ); document.write( "which results in 1 = 1 proving the value of h is correct.
\n" ); document.write( "-----
\n" ); document.write( "second equation is x * h = 1.
\n" ); document.write( "x = .193712943
\n" ); document.write( "h = 5.16227766
\n" ); document.write( "x * h = 1 proving the values for x and h are good.
\n" ); document.write( "-----
\n" ); document.write( "third equation is y * (h+2) = 1.
\n" ); document.write( "y = .13962039
\n" ); document.write( "h + 2 = 7.16227766
\n" ); document.write( "y * (h+2) = 1 proving the values for y and (h+2) are good.
\n" ); document.write( "-----
\n" ); document.write( "we started off with \"%28x%2By%29+=+1\"
\n" ); document.write( "we then got \"%28x%2Ah%29+=+1\"
\n" ); document.write( "we then got \"%28y%2A%28h%2B2%29%29+=+1\"
\n" ); document.write( "we then got \"x+=+%281%2Fh%29\"
\n" ); document.write( "we then got \"y+=+%281%2F%28h%2B2%29%29\"
\n" ); document.write( "we then substituted in \"%28x%2By%29+=+1\" to get \"%28%281%2Fh%29+%2B+%281%2F%28h%2B2%29%29%29+%2A+3+=+1\"
\n" ); document.write( "we then solved for h.
\n" ); document.write( "-----
\n" ); document.write( "once we solved for h we were then able to complete the problem.
\n" ); document.write( "-----
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