Question

4 years from now ,prakash's age will be 4 times his son's age.12 years from now, he
will be 2.5 times his son's age.find their present ages?

Answer 1

Let the age of son = x

Let age of prakash = y

Age of prakash after 4 years = y+4

Age of his son after 4 years = x+4

ATQ
Y+4 = 4(x+4)

y+4 = 4x + 16

y-4x = 12........eq1.


After 12 years

Son's age = x + 12
Prakash's age = y+12

ATQ
y+12 = 2.5(x+12)
y+ 12 = 2.5x + 30
Y = 2.5x+18....eq.2

Substituting the value of Y in eq1 we get,

2.5x+18-4x = 12
2.5x-4x = -6
-1.5x = -6
X = 4

Putting value of x in eq.2 we get

Y = 2.5 ×4 +18
Y = 10+18
Y = 28

Son's age = 4years
Prakash's age = 28 years


Hope this helps you..!:)

Answer 2

HI !

Let the present age of son be  x  and that of Prakash be " y"

Ages after 4 yrs :-
 Age of Prakash after 4 years = y+4
Age of his son after 4 years = x+4
--------------------------------

Given ,
y+4 = 4(x+4)

y+4 = 4x + 16

4x - y = -12  ---> [1]
------------------------

ages after 12 years :-

Son's age = x + 12
Prakash's age = y+12

given ,
y+12 = 2.5(x+12)
y+ 12 = 2.5x + 30
y = 2.5 x + 18 

putting this value in equation  1 , we get ,

[2.5x + 18 ] - 4x = 12
2.5x - 4x = -6

-1.5x  = -6

X =  4



y = 2.5 × (4) +18
y = 10 + 18
y = 28

Son's age = 4 yrs
Prakash's age = 28 yrs