In what proportion should 95% alcohol be mixed with 30% alcohol to make 70% alcohol?

To find the proportion in which the two alcohols should be mixed to obtain a desired concentration, we can use a basic mixture equation. Let's assume we have x liters of 95% alcohol and y liters of 30% alcohol.

The total volume of the mixture will be x + y liters.

Now, let's consider the concentration of alcohol in the mixture. We want to have a 70% concentration of alcohol.

To calculate the concentration, we need to consider the amount of pure alcohol in each component of the mixture. In the 95% alcohol, x liters contain 0.95x liters of pure alcohol, while in the 30% alcohol, y liters contain 0.3y liters of pure alcohol.

Now, we can set up an equation based on the amount of pure alcohol:

0.95x + 0.3y = 0.7(x + y)

Simplifying the equation:

0.95x + 0.3y = 0.7x + 0.7y

0.95x - 0.7x = 0.7y - 0.3y

0.25x = 0.4y

Simplifying further:

x/y = 0.4/0.25

Dividing both sides by y:

x/y = 1.6

So, the proportion in which the 95% alcohol should be mixed with the 30% alcohol to obtain a 70% alcohol mixture is 1.6:1.

To calculate the actual volumes, you can choose any value for y and find the corresponding x using the equation above. For example, if you set y = 1 liter, then x = 1.6 liters, and the mixture would be 1.6 liters of 95% alcohol mixed with 1 liter of 30% alcohol.