Question 350066
.20*4+.15X=.17(X+4)
.8+.15X=.17X+.68
.15X-.17X=.68-.80
-.02X=-.12
X=-.12/-.02
X=6 OZ. OF 15% SOLUTION IS USED.  
PROOF:
.20*4+.15*6=.17(6+4)
.8+.9=.17*10
1.7=1.7