Bheja Fry question

 Question

A is 9 year older than B. In 10 years, A will be twice as old as B was 10 years ago. 

What is the present age of A and  B  ?? 

Answer

Let the age of A is x. 

Let the age of B is y. 

At present,  A is 9 year older than B

== >>      x =   y  +  9

In 10 years,  A age  x  +  10

In 10 years, B age y  -  10

It is given that A will be twice the age of B who was 10 years ago. 

==>>    x  +  10   =   2  (  y  - 10  ) 

Now substitute  x  =  y +  9

y  +  9  +  10  =  2y  -  20

y  +  19  =  2y  -  20

y =   39

Now substitute y in  x = y + 9

x =  48

Hence,

Present age of A  =  x  =  48

Present age of B  =  y =  39