document.write( "Question 30014: 6. Gary hung seven strings of holiday lights on his house. Some strings had 75 lights and the rest had 100 lights per string. When a fuse blew. One-third of the lights went out but 400 lights still worked. How many of the seven strings had 75 lights? \n" ); document.write( "
Algebra.Com's Answer #16758 by josmiceli(19441)\"\" \"About 
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Gary hung seven strings of holiday lights on his house.
\n" ); document.write( "x = # strings with 75 lights
\n" ); document.write( "7 - x = # strings with 100 lights
\n" ); document.write( "75x + 100(7 - x) = 400 + (75x + 100(7-x))/3
\n" ); document.write( "3(75x + 100(7-x)) = 1200 + 75x + 100(7 - x)
\n" ); document.write( "225x + 300(7 - x) = 1200 + 75x + 100(7 - x)
\n" ); document.write( "225x + 200(7 - x) = 1200 + 75x
\n" ); document.write( "150x + 1400 -200x = 1200
\n" ); document.write( "-50x + 1400 = 1200
\n" ); document.write( "-50x = -200
\n" ); document.write( "x = 4
\n" ); document.write( "7 - x = 3
\n" ); document.write( "There are 4 strings with 75 lights and 3 strings with 100 lights
\n" ); document.write( "check
\n" ); document.write( "75*4 + 100(7 - 4) = 400 + (75*4 + 100(7-4))/3
\n" ); document.write( "300 + 300 = 400 + (300 + 300)/3
\n" ); document.write( "600 = 400 + 200
\n" ); document.write( "600 = 600
\n" ); document.write( "OK \n" ); document.write( "
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