Question

Father's age is three times the age of his son. Five years later, father will be two and half time as old as his son. Father age is....

Answer 1

Answer:

45

Step-by-step explanation:

Let f be the father's age.

Then "father's age is three times the age of his son" tells us that the son's age is f/3.

Five years later, the father's age will be f+5 and the son's age will be f/3 + 5.  We are told that the father's age will be 2.5 = 5/2 times that of his son, so:

f + 5 = 5/2 ( f/3 + 5 )

=> 2f + 10 = 5 ( f/3 + 5 )          [ multiplied by 2 ]

=> 6f + 30 = 5 ( f + 15 )           [ multiplied by 3 ]

=> 6f + 30 = 5f + 75

=> f = 75 - 30 = 45

Answer 2

Answer:

Step-by-step explanation:

Let son's age be X

So father's age is 3x

After 5 years

Son's age=X+5

Father's age=3x+5

But given

3x+5=5/2(X+5)

3x+5=(5x+25)/2

6x+10=5x+25

6x-5x=25-10

x=15

Therefore son's current age is 15yrs

So father's age =3×15=45yrs