<PRE><B>Question 1168918</B>
x oz of A for 0.20x pure salt
140-x oz of B for 63-0.45x pure salt
the total amount of pure salt desired is 140*0.3=42 oz.


sos 0.2x+63-0.45x=42
-0.25x=-21
x=84 oz of 20% one answer
140-x=60 oz  of 45% the other answer

check
30% is 2/5 of the way from 20 to 45, so more of the 20% will be used.
84 oz is 3/5 of the total amount, weighting the final proportions towards the lesser concentration.</PRE>