Question 368755
Let a = #oz. of solution A
Then 60-a = # oz. solution B.  Then 
0.60a +0.85(60-a) = 0.70*60,
0.60a + 51 - 0.85a = 42,
-0.25a = -9,
a = 36 oz. of solution A, and 24 oz. of solution B.