Allegation is a method to find the ratio in which two or more indignant are mixed to produce a mixture or solution.
The equation represents the total liters of acid that are needed is,
[tex]0.5x+0.9y=6[/tex]
Thus the option 3 is the correct option.
Allegation is a method to find the ratio in which two or more indignant are mixed to produce a mixture or solution.
Given information-
A scientist needs 10 L of a solution that is 60% acid.
The percentage of two acid solution are 50% and 90%.
Variable x represent the number of liters of the 50% solution.
Variable y represent the number of liters of the 90% solution.
Quantity of acid from 50% solution is [tex]0.5x[/tex] liters, and quantity of acid from 90% solution is [tex]0.9x[/tex] liters.
As the scientist needs 10 L of a solution that is 60% acid. Therefore the quantity of acid in 60 percent acid solution is,
[tex]a=10\times\dfrac{60}{100} \\a=6[/tex]
Thus 6 liters of acid required by the scientist. As to get the 6 liters of acid from 50% and 90 percent solution, we need to add the amount of acid in these solutions.Thus,
[tex]0.5x+0.9y=6[/tex]
This is the required equation.
Hence the equation represents the total liters of acid that are needed is,
[tex]0.5x+0.9y=6[/tex]
Thus the option 3 is the correct option.
Learn more about the mixture and allegation here;
https://brainly.com/question/24372098