In the lab, Amanda has two solutions that contain alcohol and is mixing them with each other. She uses twice as much Solution A as Solution B. Solution A is 11% alcohol and Solution B is 18% alcohol. How many milliliters of Solution B does she use, if the resulting mixture has 320 milliliters of pure alcohol?

1,103.47 milliliters

Explanation:

The total percentage of alcohol from solution A and solution B is 29. In a solution that is a mixture of solution A and B, the percentage of alcohol that would be contributed by solution A would be:--

                   11/29 x 100% = 37.93%

--while the percentage of alcohol that would be contributed by solution B would be:

               18/29 x 100 = 62.07%

Hence, if a mixture of A and B has 320 milliliters of alcohol, the amount of alcohol contributed by B would be:

                     320 x 62.07/100 =  198.624 milliliters

Now, remember that solution B is 18% alcohol. This means that the 18% alcohol content of solution B is 198.624 milliliters. Thus, the total volume of solution B would be:

                 198.624 x 100/18 = 1,103.47 milliliters.

Therefore, the total milliliters of solution B Amanda used would be 1,103.47.

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