Question 1181854
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Let x be the price for 1 pound of tin, in dollars;  then the price for 1 pound of copper is (x-1)  dollars.


The total cost is the sum of costs of ingredients.


    4x + 6*(x-1) = (4+6)*4.15


Simplify and solve


    10x = 10*4.15 + 6 

    10x = 47.50

      x = {{{47.50/10}}} = 4.75.


<U>ANSWER</U>.  A pound of tin is worth  $4.75.


<U>CHECK</U>.   The total cost of ingredients is  4*4.75 + 6*(4.75-1) = 41.50 dollars,

         same as the total cost of the alloy  4.15*(4+6) = 41.50  dollars.    ! Correct !
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Solved.