Question

How many gallons of a 70​% antifreeze solution must be mixed with 60 gallons of 20​% antifreeze to get a mixture that is 60​% ​antifreeze? Use the​ six-step method.

Answer 1

We have 60 gallons of 20% antifreeze.

How much 70% antifreeze do we add to get 60% antifreeze?

We'll make "x" the gallons of 70% we must add.

.20 * 60 + .70 x = .60 * (60 + x)

12 + .70x = 36 + .60x

.10x = 24

x = 240 gallons of 70% antifreeze.

Source

1728.com/mixture.htm (see example B)