charge depreciation @10%p.a for two months …

Explanation:

machine costing = 300000

calculate depreciation under straight line method

depreciation for two months = [ ( 300000 * 10 % ) * 2/12 ]

                                                   = 5000

machinery cost after charging depreciation (300000 - 5000)

                                                                          =  295000

calculate depreciation under WDV method 

machine costing =                                                               300000

depreciation for 1st month = [ ( 300000 * 10 % ) * 1/12 ] =  -2500

                                                                                              = 297500

depreciation for 2nd month = [ ( 297500 * 10 % ) * 1/12 ] =  -2480

                                                                                             =   295020