Question

in the lab, keith has two solutions that contain alcohol and is mixing them with each other. Solution A is 20% alcohol and solution B is 6% alcohol. He uses 400 ml of Solution A. How many ml of solution b does he use?

Answer 1

The question is incomplete, here is the complete question:

In the lab, keith has two solutions that contain alcohol and is mixing them with each other. Solution A is 20 % alcohol and Solution B is 6 % alcohol. He uses 400 milliliters of Solution A. How many milliliters of Solution B does he use, if the resulting mixture is a 12% alcohol solution?

Answer: The volume of solution B used is 533.3 mL

Explanation:

We are given:

Volume percent of alcohol in solution A = 20 %

Volume percent of alcohol in solution B = 6 %

Let the volume of solution B used be 'x' mL

Volume of solution A used in the mixture = 400 mL

Total volume of the mixture = (400 + x) mL

Calculating the volume of solution B used:

$\Rightarrow (20\% \text{ of }400)+(6\% \text{ of }x)=12\% \text{ of }(400+x)$

$\Rightarrow (\frac{20}{100}\times 400)+(\frac{6}{100}\times x)=\frac{12}{100}\times (400+x)\\\\\Rightarrow 80+0.06x=0.12(400+x)\\\\\Rightarrow 0.06x=32\\\\\Rightarrow x=\frac{32}{0.06}=533.3mL$

Hence, the volume of solution B used is 533.3 mL