document.write( "Question 157183: A group of ten 6 and 12 volt batteries are wired in series; the sum of their voltages is 84 volts. How many of each type of battery are used?\r
\n" ); document.write( "\n" ); document.write( "6x + 12x = 84
\n" ); document.write( "18x = 84 does not work \n" ); document.write( "
Algebra.Com's Answer #115836 by Alan3354(69443)\"\" \"About 
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A group of ten 6 and 12 volt batteries are wired in series; the sum of their voltages is 84 volts. How many of each type of battery are used?
\n" ); document.write( "6x + 12x = 84
\n" ); document.write( "18x = 84 does not work
\n" ); document.write( "-------------
\n" ); document.write( "Call the 12V batteries T and the 6V S
\n" ); document.write( "There is a total of 10 batteries, so
\n" ); document.write( "T+S=10
\n" ); document.write( "12T + 6S = 84
\n" ); document.write( "-----------
\n" ); document.write( "T=10-S
\n" ); document.write( "Sub for T
\n" ); document.write( "12(10-S) + 6S = 84
\n" ); document.write( "120-12S + 6S = 84
\n" ); document.write( "120 -6S = 84
\n" ); document.write( "-6S = -36
\n" ); document.write( "S = 6
\n" ); document.write( "T = 4\r
\n" ); document.write( "\n" ); document.write( "Check:
\n" ); document.write( "6*6 + 12*4 does = 84\r
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