document.write( "Question 419129: A glue company needs to make some glue tat it can sell at $120 per barrel.It wants to use 150 barrels of glue worth $100 per barrel, along with glue worth $150 per barrel and and glue worth $190 per barrel.It must use the same number of barrels of $150 and $190 glue.How much of the $150 and $190 glue will be needed?How many Barrels of $120 glue will be produced? \n" ); document.write( "
Algebra.Com's Answer #853240 by greenestamps(13327)\"\" \"About 
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\n" ); document.write( "Another tutor has provided a standard formal algebraic solution to the problem. But the numbers in this problem make it a good one for solving informally using logical reasoning instead of formal algebra.

\n" ); document.write( "Since equal amounts of the glues worth $150 per barrel and $190 per barrel are to be used, the average cost of those two ingredients is halfway between those two prices, which is $170 per barrel.

\n" ); document.write( "Then the problem becomes mixing glue worth $100 per barrel with glue worth $170 per barrel to get glue worth $120 per barrel. The ratio in which those two ingredients must be mixed is exactly determined by where the $120 price lies between the $100 and $170 prices.

\n" ); document.write( "The difference between $100 and $120 is $20; the difference between $120 and $170 is $50. Those differences mean the two ingredients must be mixed in the ratio 20:50 = 2:5.

\n" ); document.write( "Because $120 is closer to $100 than it is to $170, the larger portion must be the ingredient worth $100 per barrel. So the mixture needs to be 5 parts of the glue worth $100 per barrel and 2 parts of the glue worth $170 per barrel.

\n" ); document.write( "Given that there are 150 barrels of glue worth $100 per barrel, use a proportion to find that we need 60 barrels of the glue worth $170 per barrel:

\n" ); document.write( "\"150%3A5=x%3A2\"
\n" ); document.write( "\"5x=300\"
\n" ); document.write( "\"x=60\"

\n" ); document.write( "Then, since the glue worth $170 per barrel is equal amounts of the glues worth $150 and $190 per barrel, there must be 30 barrels each of the $150 per barrel glue and the $190 per barrel glue.

\n" ); document.write( "ANSWERS:
\n" ); document.write( "(1) 30 barrels each of the $150 per barrel and $190 per barrel glue will be used
\n" ); document.write( "(2) The total number of barrels of glue will be 150+30+30 = 210

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