The present age of a Manoj is twice the sum of the ages of his two children. After 20 years, the age of Manoj will become equal to the sum of the ages of his two children. Whatis the present age of Manoj?

Let       Present Age of Manoj = m

             Sum of Present ages of two children = s

Given, Present Age of Manoj is twice the sum of both children

$$=$$>         m= 2s ..................(1)

After 20 years, Sum of Ages of two children = s+20+20

                                                                              = s+40

According to Problem, After 20 years age of Manoj is equal to the Sum of Ages of both children

$$=$$>        m+20 = s+40

                     m = s+20............(2)

From equations (1) and (2)

                      2s = s+20

                         s = 20

Therefore, Present Age of Manoj = 2m

                                                           = 2$$\times\ $$20

                                                           = 40 years