Depreciation.

Hi can you please explain this question to me. I dont understand how the remaining useful life after revaluation is 13.5 years. Please explain in detail if possible. Thank you!
This question is from the Kaplan Exam Kit, Question 11.

The following trial balance extract relates to a property which is owned by Veeton as at 1 April 20X4.

Property at cost $12000 Dr
Accumulated Depreciation as at 1 April 20X4 $3600 Cr

On 1 October 20X4, following a sustained increase in property prices, Veeton revalued its property to $10.8 million.
What will be the depreciation charge in Veeton’s statement of profit or loss for the year ended 31 March 20X5?