以下是一到关于折旧的一道很简单的题，请大家帮忙看一下：

Santa runs a large toy shopm In the year ended 31 August 2005. SHe bought the following fixed assets:

A new cash register for $5,000. this was purchased on 1 December 2004, and was to be depreciated at 10% straight line

A new delivery van, purchased on 31 March 2005, at a cost of $22,000. the van is to be depreciated at 15% reducing balance.

Santa charges depreciation on a monthly basis

What is depreciation charge for the year ended 31 August 2005?

讲义上的答案如下：

Cash register   10%*5,000*9/12=375

Delivery van     15%*22,000*5/12=1,375

我的疑问是： Delivery van depreciation is charged by reducing banlance method as mentioned, why does it use the straight line method to calculte? 

Santa charge depreciation on monthly basis means every month she recorded the depreciation but not recorded as a lump sum amount.

Depreciation we calculate on a basis of financial year, reducing balance method means year by year not month by month.