Answer:
Sam is yeas old, and Dean is (x - 10) year's old, where 'x' is the age of their sister
Step-by-step explanation:
The relationship between the ages of the brothers are;
Sam's age + Dean's age = Their sister's age
Dean's age + 10 = Dean's age + Sam's age
Therefore, we have;
Sam's age = Dean's age + 10 - Dean's age = 10
Sam's age = 10 years
Let 'x' represent their sisters age, we get;
Sam's age + Dean's age = x
10 + Dean's age = x
Dean's age (in variable form) = x - 10