Sep 16 examiner report

Hello Sir, "The second question that caused difficulty was the treatment of profit on a sale and leaseback arrangement. The profit is the difference between the sale proceeds and the carrying amount (at the time of the sale and leaseback) and this is spread over the remainder of the asset's useful life or, if shorter, the remaining lease term." what means the profit is spread over the remainder of the assets useful life? can you give an example? Thank you.