Question 1
It is easy, just write the problem in slightly more mathematical manner:

father's age = 13 * son's age
son's age + 10 = (father's age + 10 )/3

Because we know that father's age is 13* son's age, we have

son's age + 10 = (13*son's age + 10)/3

or

3*(son's age + 10) =  (13*son's age + 10)

or 

3*son's age + 30 = 13*son's age + 10
20 = 10 * son's age

<B>ANSWER:</B>

son's age = 2
father's age = 13*2 = 26.