The following table presents the number of units of a product produced and sold by a company during six years.

What is the ratio of the total number of units of the product sold in 2013 and 2015 to that produced in 2015 and 2016?

3 : 4

Total number of product sold in 2013 & 2015  :  Total number of product produced in  2015 & 2016

   ( 328 + 242 )  :  ( 256 + 504 )

          570         :        760

            3           :          4