Question

the difference between ages of gopal and his father is 26 years if the some of their ager 47 yearsfind age of his son and father

Answer 1

There are two possibilities. Either assume that ages can be in decimals too. Or, we say that the data given is not right.

Father + Son = 47 years
Father - Son = 26 years

Sum both equations to get Father's age.
     Father = 73/2 = 36.5 years or 36 years 6 months.

So use the first equation to get Son's age.
      Son = 47 - 36.5 = 10.5 years or 10 years and 6 months.