Question

How many gallons of a 80​% antifreeze solution must be mixed with 100 gallons of 20​% antifreeze to get a mixture that is 70​% antifreeze? Use the​ six-step method.

Answer 1

To Find :

How many gallons of a 80​% antifreeze solution must be mixed with 100 gallons of 20​% antifreeze to get a mixture that is 70​% antifreeze.

Solution :

Let, x gallons of 80​% antifreeze solution is required :

So,

$(x \times 80) + ( 100 \times 20 ) = (x + 100 )\times 70\\\\8x + 200 = 7( x + 100)\\\\x = 500$

Therefore, 500 gallons of 80% antifreeze solution is required.