If digits of my age are reversed you will get my son's age…

If the digits of my present age are reversed then I get current age of my son.
If one year ago my age was twice the age of my son. Find my present age.

Solution:

Age related questions are quite popular in the test of IT companies (esp. at junior level). All such questions reuire you to establish an equation and solve that equation.
Let father’s age have 2-digits in it and they are X and Y. Hence, the current age of father is:

10.X + Y

Current age of Son will be

10.Y + X

Last year ages of Father & Son were respectively

(10.X + Y -1) and (10.Y + X - 1)

According to question (last year, Father’s age was twice as Son’s age)

(10.X + Y -1) = 2 * (10.Y + X - 1)

=> 8X = 19Y - 1

Now X & Y are Single digits only (and not fractions or multiple digit numbers). Hence both of them has to from the set {0,1,2,3,4,5,6,7,8,9}. Lets replace one digit at a time for X and see the value of Y.. For example:

if X = 0 => Y=1/19

Hence, this is not the answer.
Similarly if you continue to replace the digits, you will get

X = 7 & Y = 3

Hence,

Father’s Age = 73
Son’s Age = 37

(Last year their ages were 72 & 36 and father was twice as old as son)