Question 1151890
Too many doublings in your description.

<pre>
COFFEE     PRICE      QTY       COST
A          $15.21      x       15.21x
B          $13.99      y       13.99y
C          $11.24     2x       22.48x
--------------------------------------------
TOTAL                 51
</pre>


The quantity equation is obvious.  


The PRICE equation for the given 13.45 per pound is the sum of the COST column items divided by 51,  equal to 13.45.


Setup the system , simplify and solve.