Sit-on-Top offers bus tours along the Jurassic Coast. It purchased a bus on 2 January 20X4 for N$170 000. The bus has a total estimated useful life of 5 years. At 31 December 20X5, the end of the 20X5 financial year,

• Similar busses that are new are selling for N$175 000;

• Similar busses that are 1 year old are selling for N$100 000;

• Similar busses that are 5 years old are selling for N$40 000;

• Similar busses that are 4 years old are selling for N$65 000.

For purposes of estimating depreciation for the year ended 31 December 20X5, the residual value of the bus is: