Question

How many gallons of a 80% antifreeze solution must be mixed with 90 gallons of 10% antifreeze to get a mixture that is 70% St
antifreeze? Use the six-step method.

Answer 1

We have 100 gallons of 25% antifreeze.
How much of 80% antifreeze do we need to
add to make a 70% solution?
.25 * 100 + .80x = .70 * 100 + x
25 + .80x = 70 + .7x
.1x = 45
x = 450 gallons of 80% must be added to
make a 70% solution.