document.write( "Question 1163992: Acetaminophen is a medicine used to relieve pain and reduce fevers. However, when administering acetaminophen to infants and children, the dosage must be controlled carefully. Otherwise, there could be fatal consequences, such as kidney failure. The dosage usually varies directly as the weight of the child. When a baby weighs 25 pounds, the recommended dosage is 160 mg. Using the previous information, what
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\n" ); document.write( "(Is this a direct variation problem or an inverse variation problem? What key words in each problem tell you that it is either a direct variation or inverse variable problem?)
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Algebra.Com's Answer #788277 by ikleyn(52797) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( " Since the problem says \"The dosage usually varies directly as the weight\", \r
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document.write( "1.  These words mean that the dosages and the weights of patients are proportional.\r\n" );
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document.write( "    So, you can write a proportion\r\n" );
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document.write( "         = ,     (1)  \r\n" );
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document.write( "    or\r\n" );
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document.write( "         = ,               (2)\r\n" );
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document.write( "    where x is the unknown dosage under the problem's question.\r\n" );
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document.write( "    From proportion (2),  x =  = 160*3 = 480 mg.     ANSWER\r\n" );
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document.write( "2.  You can also write the base proportion (1) in other form \r\n" );
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document.write( "         = ,     (3)  \r\n" );
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document.write( "    or\r\n" );
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document.write( "         =                 (4)\r\n" );
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document.write( "    From the proportion (4),  you get the same answer\r\n" );
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document.write( "        x =  = 160*3 = 480 mg.\r\n" );
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document.write( "3.  Instead of using proportions, you can use common sense/reasoning, which tells you that if in the second case \r\n" );
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document.write( "    the body weight is 3 times as much as in the first case (as you have   = 3), then the dosage in the second case \r\n" );
document.write( "    should be 3 times as much as in the first case.\r\n" );
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\n" ); document.write( "\n" ); document.write( "By doing in this way, you avoid calculating an intermediate coefficient of proportionality \"k\",\r
\n" ); document.write( "\n" ); document.write( "which you do not need and which is simply an auxiliary value. You directly obtain then the requested/required answer,\r
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\n" ); document.write( "\n" ); document.write( " These straightforward approaches work always and every time, \r
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document.write( "The terms \r\n" );
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document.write( "    -  \"one value varies directly as the second value\", \r\n" );
document.write( "    -  \"the values are in direct proportion\"   and \r\n" );
document.write( "    -  \"the values are proportional\" \r\n" );
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document.write( "are synonymous (i.e. EQUIVALENT by their meaning).\r\n" );
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\n" ); document.write( "\n" ); document.write( "On proportions, see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Proportions\r
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\n" ); document.write( "\n" ); document.write( "    - Using proportions to solve Chemistry problems\r
\n" ); document.write( "\n" ); document.write( "    - Typical problems on proportions \r
\n" ); document.write( "\n" ); document.write( "    - Using proportions to estimate the number of fish in a lake\r
\n" ); document.write( "\n" ); document.write( "    - HOW TO algebreze and solve these problems using proportions \r
\n" ); document.write( "\n" ); document.write( "    - Problems on proportions for mental solution \r
\n" ); document.write( "\n" ); document.write( "    - Selected problems on proportions from the archive \r
\n" ); document.write( "\n" ); document.write( "    - OVERVIEW of lessons on proportions\r
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\n" ); document.write( "\n" ); document.write( "These lessons were written specially for you. \r
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in this area.\r
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\n" ); document.write( "\n" ); document.write( "Start from the very first lesson.\r
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\n" ); document.write( "\n" ); document.write( "Consider these lessons as your textbook, handbook, tutorials and (free of charge) home teacher.\r
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\n" ); document.write( "\n" ); document.write( "After reading the comment by Edwin.\r
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document.write( "    Edwin, thank you for your comment which you sent to me.\r\n" );
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document.write( "    Be sure, I always read very attentively every your post . . . \r\n" );
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document.write( "    Edwin, I think that it is great as you presented your post and your approach, which is a DOMINANT in school teaching.\r\n" );
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document.write( "    I know it VERY WELL, so it is not something new to me.\r\n" );
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document.write( "    But I think that if the student knows BOTH APPROACHES, he (or she) will have GREATER BENEFITS.\r\n" );
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document.write( "    Also, let me add THIS: I think that if the student knows your approach (=standard), but does not know\r\n" );
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document.write( "    my interpretation, it means that he (or she) does not know and does not understand ANYTHING in the subject.\r\n" );
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document.write( "    So, what I explained in my post, is actually a prerequisite for that problem.\r\n" );
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