Question

A fathers age is 3 times sum of his two children children's age .after 5 years he'll be twice as his children's age .find their age !

Answer 1

Answer :-

Children age = 15 years

Father age = 45 years

Given :-

A father is 3 times sum of his children.

Five years hence he will be twice as his children age.

To find :-

Children age and his father age.

Solution :-

Let the age of father be x years

And the age of his two children be y years.

A/Q

$x = 3y$

After 5 years.

Father age will be ( x + 5 ) years

children age will be ( y + 10 ) years

Now, $x = 3y$-----eq.1

$( x +5) = 2 ( y + 10)$------eq.2

$x + 5 = 2y + 20$

Put x = 3y

$\implies$ $3y + 5 = 2y + 20$

$\implies$ $3y -2y = 20 -5$

$\implies$ $y = 15 years$

hence, children age will be = 15 years .

Father age will be = 3y = 3 × 15 = 45 years.

Answer 2

Answer:

Let children's age be x and y

Father's age = 3 (x + y ) = 3x +3y

After 5 years,

children's age be (x+5) +(y+5) = x +y +10

Father's age = 3x +3y + 5

A/q

3x +3y +5 = 2( x +y +10)

=》3x +3y +5 = 2x + 2y +20

=》3x -2x + 3y -2y = 20

=》x+ y = 20

Father's age = 3(x + y) = 3 ×20 = 60years