Could you please explain as detailed as possible? Honestly, I already have the answer to this so I just want to understand more detail.

- On 1 September 2012, a company which prepares financial statements to 31 December each year classifies a disposal group as held for sale. This disposal group is still unsold at 31 December 2012. The carrying amount of the disposal group's assets and liabilities at 1 September 2012 are shown below, along with the carrying amount as which these assets and liabilities would have been measured at 31 December 2012 (in accordance with applicable standards) if the group had not been classified as held for sale. The fair value (less costs to sell) of the disposal group is 8 million at 1 September 2012 and 7,5 million at 31 December 2012. Calculate the amount of any impairment losses or gains that should be recognised at: (a) 1 September 2012 (b) 31 December 2012 . Show how these impairment losses and gains should be allocated amongst the assets and liabilities in the group. (9 p.)