For “Age” related problems:
1. Form an equation.
2. Simplify the equation.
3. Use the back-calculation method.
4. Don't choose unnecessary fractional variables that will complicate the equation. Suppose, in the question, it said that son's age is 2/5th of the father's age. Instead of choosing ‘x’ as a variable for the father's age, choose ‘5x’. Then the son's age will be 2x instead of 2x/5.
Video on "Age Related Math Problems":