Question

A man is 4 times as old as his son.
After four years the man will be thrice as old as his son
find their present ages​​

Answer 1

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Let the present ages of man and son be 'x' and 'y'

After 4 years :

Age of man = x + 4

Age of son = y + 4

From the data ,

x = 4y .... (i)

(x + 4) = 3(y + 4)

x + 4 = 3y + 12 .... (ii)

Substituting x = 4y in eq(ii) ,

x + 4 = 3y + 12

4y + 4 = 3y + 12

4y - 3y = 12 - 4

y = 8

Substituting y = 8 in x = 4y

x = 4y

:. x = 4(8) = 32

Present age of man = 32

Present age of son = 8

Answer 2

Explanation:

Let Present age of Son be = x years

So, Present age of Man will be = 4x years

After 4 years

Age of Man = ( 4x + 4 )

Age of Son = ( 4x + 4 )

According to the question :-

$(4x + 4) = 3(x + 4)$

$4x + 4 = 3x + 12$

$4x - 3x = 12 - 4$

$x = 8 \: years$

So, present age of Man = 4x = 4 × 8 = 32 years

and present age of Son = x = 8 years