Hello, MathMinors!

How many liters of water must be added to 35 liters of 80% HCl solution

to reduce its strength to 75%?

Ans: 6.53 liters . . . . Wrong!

We concerned with the amount ofwaterto be added.

The amount ofis our concern.water

We start with 35 liters of soluton which is 20% water,

. . It contains:. liters of water.

We add liters of water.

The mixture contains:. liters of water. .[1]

We know that the mixture will contain liters of which 25% is water.

. . The mixture contains:. liters of water. .[2]

We just described the final amount of water intwo ways.

There is our equation . . .

Solve for

. . . . . . . . . .