The above rule has been made to meet such an eventuality, and reads as under: "In any case in which the Income tax Officer is of opinion that the actual amount of the income, profits or gains accruing or arising to any person residing out of the taxable territories whether directly or indirectly through or from any business connection in the taxable territories or through or from any property in the taxable territories, or through or from any asset or source of income in the taxable territories, or through or from any money lent at interest and brought into the taxable territories in cash or in kind cannot be ascer tained, the amount of such income, profits or gains for the purposes of assessment to income tax may be calculated on such percentage of the turnover so accruing or arising as the Income tax Officer may consider to be reasonable, or on an amount which bears the same proportion to the total profits of the business of such person (such profits being computed in accordance with the provisions of the Indian Income tax Act) as the receipts so accruing or arising bear to the total receipts of the busi ness or in such other manner as the Income tax Officer may deem suitable.