Question 539307
A man wants to blend 30kg of coffee and each kilo cost $4.80.
One brand of coffee cost $6 dollars and $4 dollars for a kilo. How
much kilos of each brand of coffee should be used?
<pre>
Suppose we mix x kg of the $6 coffee with y kg of the $4 coffee.
Then we have two equations, a coffee equation and a money equation:

The coffee equation comes from

         {{{(matrix(6,1,x, kgs, of, more, expensive, coffee))}}} + {{{(matrix(6,1,y, kgs, of, less, expensive,coffee))}}} = {{{(matrix(7,1,30, kgs, of, medium, priced, mixed, coffee))}}}  


                          x + y = 30

The money equation comes from
    
         {{{(matrix(8,1,"$6", times, x,kgs, of, more, expensive, coffee))}}} + {{{(matrix(8,1,"$4", times,y, kgs, of, less, expensive,coffee))}}} = {{{(matrix(9,1,"$4.80", times,30, kgs, of, medium, priced, mixed, coffee))}}}  

                        $6x + $4y = ($4.80)(30)
                          6x + 4y = 144

So solve this system of equations:

                         x +  y =  30
                        6x + 4y = 144


Answer: Mix 12 kgs of the more expensive coffee and 18 kgs of the cheaper coffee

Edwin</pre>