Question 740890
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The coffee merchant wants to blend a mildly strong coffee called Nervous Nellie with an extremely strong coffee called Nervous Breakdown to create 
a medium strength coffee he plans to call Nervous Wreck. If the Nellie flavor costs $1.20 per pound and the Breakdown flavor costs $1.40 per pound, 
how many pounds of the Nellie is needed to create a 30 pound blend which costs $1.35 per pound?
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Let x be the number of pounds of the $1.20 per pound coffee (Nellie).

Then the number of pounds of the $1.40 per pound coffee (Breakdown) is (30-x).


Write the total money equation

    1.20x + 1.40(30-x) = 30*1.35  dollars.


Simplify and find x

    1.20x + 1.40*30 - 1.40x = 30*1.35

     -0.2x = 30*1.35 - 30*1.40

     -0.2x = 30*(1.35-1.40)

     -0.2x = 30*(-0.05)

     0.2x = 30*0.05

        x = {{{1.5/0.2}}} = {{{15/2}}} = 7.5 pounds.


<U>ANSWER</U>.  7.5 pounds of the Nellie coffee is needed.


<U>CHECK</U>.   {{{(1.20*7.5 + 1.40*(30-7.5))/30}}} = 1.35 dollars per pound, the price for the pound of the blend.  ! correct !
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Solved.


The answer 4 1/2 pounds in the post by @lynnlo is incorrect.