Father told daughter when I was your age you are 4 yrs old . When you will be of my age ,I will be 79 yrs old.what is the age of Father and daughter now?

Question

Father told daughter when I was your age you are 4 yrs old . When you will be of my age ,I will be 79 yrs old.what is the age of Father and daughter now?

Answer 1

I had to do this by guess and check.  I hope someone can give you equations...

 

If daughter is 29, that means dad had her at 25.  Now, he's 25 + 29 =54.  when daughter is 54, 25 years will have passed.

 

Dad is now 54 + 25 = 79 years old.

Answer 2

a = the age difference between the father and daughter = the age the father was when he had the daughter

 

f = father's age

 

d = daughter's age

 

f - a = d

 

 so f = a+d

 

d - a = 4 (a years ago, the daughter was 4)

 

d = a+ 4

 

f + a = 79  (when the daughter is as old as the father is now, in a years, he will be 79)

 

 so f = 79-a

 

 

a + d = 79 - a

 

a + (a + 4) = 79 - a

 

3a = 75

 

a = 25 = the age difference

 

d = 29 = the daughter's age

 

f = 54 = the father's age