Ascientist has 40 liters of a 50% acidic solution. she adds a 20% acidic solution to create a mixture that has been diluted to
have 30% acidity. the graph models the percent of acidity in the final mixture.
20 40 60 80
how many liters of the 20% acidic solution should be added to create the needed 30% acidity in the final mixture?

a: 0.5
b: 30
c: 80
d: 37

C. 80 liters

Step-by-step explanation:

A scientist has 40 liters of a 50% acidic solution. So, there are

of acid in this solution.

She adds x liters of 20% acidic solution to create a new mixture. In x liters of 20% acidic solution there are

of acid.

The total volume of the mixture is (40 + x) liters. This mixture has 30% acidity, so there are

of acid.

The amount of acid is the same, thus,

C) 80 L

Step-by-step explanation:

According to the dilution law,

where,

= concentration of acid solution = 50 %

= volume of acid solution = 40 L

= concentration of another acid solution= 20%

= volume of another acid solution= x L

= concentration of resulting acid solution = 30 %

= volume of resulting acid solution = (40+x) L

Putting the values in the equation:

Thus 80 L of the 20% acidic solution should be added to create the needed 30% acidity in the final mixture.

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