A certain sum of money becomes Rs. 3600 in 8 years and Rs. 4500 in 12 years at a certain rate of compound interest. Find the sum.

Rs. 2304

      Prin.      :    A₄     :      A₈     :      A₁₂

                                       3600   :     4500

                                           4    :     5

                          4      :        5

         4       :       5                                     

        16      :      ---     :       25

         ⇓                                ⇓

         ⇓                           × 144

      × 144                       =3600 (given)

      = 2304