Alligation is a practical method used to calculate the proportion in which substances of different strengths are mixed to obtain a mixture of a desired intermediate strength.
If you mix a 50% solution and a 10% solution to get a 30% solution, the ratio is 20 parts of the 50% solution to 20 parts of the 10% solution (a 1:1 ratio). To make 1000 mL, you would need 500 mL of each.
