Staunton Ltd acquires a new tractor for its pineapple farm. The tractor is expected to be operational for a period of 18 years, although a more economical version, which Staunton Ltd’s competitors will probably acquire, will be available in six years. It is envisaged that Staunton Ltd will close down in 15 years, as its existing lease will expire.

REQUIRED

Determine the number of periods over which the tractor should be depreciated.