Question

A girl is 28years younger than father the sum of their ages is 50 years find the age of girl and father

Answer 1

let age of girl be 'a'
age of father is 28+a
given that sum of their ages is 50
a+28+a=50
2a=50-28
2a=22
a=11
therefore girl is 11 years old and father is 39 years old

Answer 2

Let
    the father's age be x
    girls age be x-28                                                                                                                                      
Sum of ages = girl's age + father's age = 50
                                                                                                                               therefore,
                                                                                                                                x+(x-28) = 50
    2x - 28 = 50 
    2x        = 50 + 28
    2x        = 78
      x        = 78/2
      x        = 39    
 father's age = x = 39
 girl's age = (x - 28) = 11