help retained earnings

pls am having issues with retained earnings brought forward calculations especially when it has to do with time apportionment, e.g bpp question 39 why was the post acq retained earnings of systan 6300 in the balance sheet added to 3000 in the income statement, for date of acquisition retained earnings. Also in question 38 Bpp, also why was the 3000 of the sub skeptik not time apportioned as 9/ 12 x 3000 instead 3/12x 3000 was used? pls someone explain am getting confused about these.