(2)The written down value of the block of assets, being ships or inland vessels, as the case may be, as on the first day of the first tax year, shall be divided in the ratio of the book written down value of the qualifying ships (herein referred to as the qualifying assets) and the book written down value of the non-qualifying ships (herein referred to as the other assets), as per the following formula:––D = A x B /(B+C)E = A x C/(B+C)where,—D = the written down value of the block of qualifying assets as on the first day of the tax year;E = the written down value of the block of other assets as on the first day of the tax year;A = the written down value of the existing block of assets, being ships or inland vessel, as the case may be, as on the first day of the tax year;B = the aggregate of book written down value of qualifying assets as on the last day of the preceding tax year; andC = the aggregate of the book written down value of other assets as on the last day of the preceding tax year.