document.write( "Question 24856: Three computers can print out a spreadsheet for the Baldwin Accounting Firm in 12 minutes, 18 minutes, and 36 minutes. How long would it take to complete the task with all three computers working?\r
\n" ); document.write( "\n" ); document.write( "An athlete begins jogging at 8mph and then at 7mph, traveling a total of 10.9 miles in 1.5 hours. How long did the athlete jog at each speed? \n" ); document.write( "
Algebra.Com's Answer #13270 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
Let number of hours the three machines run be \"x\" minutes.
\n" ); document.write( "Amount of work done by a machine is (rate)(time)
\n" ); document.write( "Rate of first machine is 1/12, of second is 1/18, of third is 1/36.
\n" ); document.write( "EQUATION:
\n" ); document.write( " Works done by 1st + work done by 2nd P work done by 3rd = 1 job done
\n" ); document.write( " (1/12)x + (1/18)x + (1/36)x = 1
\n" ); document.write( " 3x + 2x + x = 36
\n" ); document.write( " 6x = 36
\n" ); document.write( " x = 6 minutes ( time to do job if all machines are running)\r
\n" ); document.write( "\n" ); document.write( "Let time run at 7mph by \"x\" hrs.
\n" ); document.write( "The time run at 8mph is \"1.5-x\" hrs.
\n" ); document.write( "Formula: d=rt
\n" ); document.write( "Distance run at 7mph is 7x miles
\n" ); document.write( "Distance run at 8mph is 8(1.5-x)= 12-8x miles
\n" ); document.write( "EQUATION:
\n" ); document.write( " Dist at 7 + Dist at 8 = 10.9 miles
\n" ); document.write( " 7x + 12-8x = 10.9
\n" ); document.write( " -x = -1.1
\n" ); document.write( " x = 1.1 (hrs. at 7mph)
\n" ); document.write( " 1.5-x = 0.4 (hrs. at 8mph)
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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