document.write( "Question 268919: a disk jocky must play 12 commercial spots during an 1 hour of radio. each commercial is either 30 or 60 seconds long. If the total commercial time during 1 hour is 8 min how many 30 second and 60 second commercials were played.\r
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Algebra.Com's Answer #197051 by CharlesG2(834)\"\" \"About 
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a disk jocky must play 12 commercial spots during an 1 hour of radio. each commercial is either 30 or 60 seconds long. If the total commercial time during 1 hour is 8 min how many 30 second and 60 second commercials were played.
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\n" ); document.write( "\n" ); document.write( "x 30 second commercials
\n" ); document.write( "y 60 second commercials\r
\n" ); document.write( "\n" ); document.write( "x + y = 12
\n" ); document.write( "1/2 * x + y = 8 (30 seconds is 1/2 minute)
\n" ); document.write( "(subsitute in y=12-x)
\n" ); document.write( "1/2 * x + 12 - x = 8
\n" ); document.write( "-1/2 * x + 12 = 8
\n" ); document.write( "-1/2 * x = -4 (divide both sides by -1)
\n" ); document.write( "1/2 * x = 4
\n" ); document.write( "x = 8 so 8 30 second commercials (4 minutes total)
\n" ); document.write( "and 4 60 second commercials (4 minutes total)\r
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