Puzzle: Age of Grand Father, Father and Grand Son

Question

One Grand Father, One Father and One Grand Son. Sum of their age is 140 Years. Grand Son's age in month is equal to Grand Father's age in years. Grand Son's age in days is equal to Father's age in weeks.

What is the Age of all three?

Answer 1

If we simplify this question then it is saying
1. Sum of the age of all three is 140
2. Grandfather age is 12 times of Grandson
3. Father age is 7 times of Grandson

Now let assume grandfather age is x, fathers is y and grandson is z. Then we have following equations

x + y + z = 140
x =12z
y = 7z 

Which gives

Grandfather age is 84 
Fathers age is 49
Grandson age is 7

Answer 2

Son is 7 yrs, Father is 49 yrs and Grandfather is 84 yrs.