Question 231287
.8x+.4*10=.6(10+x)
.8x+4=6+.6x
.8x-.6x=6-4
.2x=2
x=2/.2
x=10 liters of the 80% solution is used.
Proof:
.8*10+.4*10=.6(10+10)
8+4=.6*20
12=12