Question 84494
you're going to drain xL of 30% antifreeze leaving (16-x)L ... to this you'll add xL of 100% antifreeze to get 16L of 50%


.3(16-x)+x=.5(16) ... 4.8-.3x+x=8 ... .7x=3.2 ... x=32/7 or about 4 1/2 L