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Cost of Pencils


Date: 6/26/96 at 3:30:9
From: Susan Goh 
Subject: Algebra

Dear Dr. Math,

Drawing pencils cost 8 cents each and coloured pencils cost 11 cents 
each.  Two dozen assorted pencils cost $2.16. How many coloured 
pencils are there?

Jean
Singapore


Date: 6/26/96 at 6:9:33
From: Doctor Anthony
Subject: Re: Algebra

Let x = number of 8 cents pencils, then
 24-x = number of 11 cents pencils

Now we can write down an equation for total cost.

   8x + 11(24-x) = 216
   8x + 264 - 11x = 216
               48 = 3x

and so x = 16.   Number of drawing pencils = 16.
                 Number of coloured pencils = 8.

Check: 8*16 + 11*8 = 216   

-Doctor Anthony,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/

Associated Topics:
Middle School Algebra
Middle School Word Problems

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