Question

The age of father is *thrice* the sum of the ages of his son and daughter. After 20 years his age will be
equal to the sum of the ages of his children. Find the age of father.

Answer 1

Answer:

40

Step-by-step explanation:

Let the sum of the ages of two children will be x and age of father will be y.

A.T.Q. ,

y = 2x ----------(i)

and , After 20 years,

x+40=y+20

==> x-y= -20

put y = 2x from (i),

x-2x = -20

==> x = 20

Now, put x= 20 in (i),

y = 2 x 20 = 40

Hence age of father will be 40 years.

Answer 2

Answer:

Let the present age of son be x and daughter be y,

Then, fathers age = 3(x + y)

After 20yrs.

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

But,

A/q

Father's age = (20 +x + 20+ y)

So,

3(x + y) + 20 = (20 +x + 20+ y)

3x + 3y + 20 = 20 + x + 20 + y

3x - x = 20 + 20 - 20 + y - 3y

2x = 20 - 2y

X = 10 - 2y

And, y = 5 - x

So,

Father's present age = 3( 10-2y + 5 - x)

= 3(15-2y-x)

= 45 - 6y - 3x