Question

The mean ages of father and his son is 27yrs.after 18years ,father will be twice as old as his son.their present ages are

Answer 1

Hi,

let

at present
________

son age = x years

father age = y years

mean age of them = 27 years

( x + y ) / 2 = 27

x + y = 54 years

y = 54 - x -----( 1 )

after 18 years
__________

son age = ( x + 18 ) years

father's age = ( y + 18 ) years

according to the problem given ,

father's age = 2 × son's age

y + 18 = 2 ( x + 18)

y + 18 = 2x + 36

y = 2x + 36 - 18

y = 2x + 18 -----( 2 )

equation ( 2 ) = equation ( 1 )

2x + 18 = 54 - x

2x + x = 54 - 18

3x = 36

x = 36 / 3

x = 12

put x = 12 in equation ( 1 ) , we get

y = 54 - 12

y = 42

Therefore ,

at present ,

son's age = x = 12 years

father age = y = 42years

I hope this helps you.

:)