I have been able to work all question in the kit on tangible non-current asset but i am not able to understand the answer given in the kit for these two questions.
You are going to have to say which bit of the answers you don’t understand.
In both cases the profit is the difference between the sale proceeds and the carrying value (net book value). The carrying value is the revalued amount less the depreciation charged between the date of the revaluation and the date of sale.