You had to keep three things in mind here. First, if the entire output is being consumed, no allowance is being made to cover depreciation. Second, the capital stock will therefore decline by the amount of depreciation, leaving a capital stock of 190 at the beginning of next year. Third, while the level of output next year is 19 units, next year's income is only 9 units because 10 units have to be deducted to allow for depreciation. Remember, income is the amount that could be consumed if the capital stock and next year's output and income are to be maintained at the current year's level.
Also notice that output and income here refer to Gross and Net Domestic Product because they refer to what is produced by capital employed in the economy and not necessarily capital owned by the residents of that economy. That capital may or may not be entirely owned by domestic residents and domestic residents may also own capital employed abroad.