One of the formulas for calculating the correct dosage for a child is as follows: C = a / ((a+12)) ∙ 180 C = child's dosage in milligrams a = age of the child A = adult dosage in milligrams What is the prescribed dosage of a certain medicine for a child 6 years old, if the adult dosage of the medicine is 180 milligrams?

So you already have the formula for calculating the dosage for child with: C = a / (a+12) x 180 ml Not sure why you have double brackets

variables are: a = child's age, so everywhere you have an "a" replace it with the age of child.

Example: 5 year old child

C = 5 / (5+12) * 180 = 5 / (17) * 180 = 5/3060 =.0016 ml or milligrams