Ravi is 12 years younger than Surya. Ravi's age is 40% of the sum of his and Surya's age. What will be Surya's age after 9 years ?

45

40%= \(\frac{2}{5}\)

       Ravi : Surya  :  Sum   : Difference

        2     :    3      :    5     :        1

                                                  ↓ x12

                                                 12 (given) 

1R  = 12

Surya's age at present = 3 × 12 = 36 years

Surya's age after 9 years = 36 + 9 = 45 years