Stocks and flows

Correct answer: B. Flow

Explanation: Investment represents expenditure on acquiring or creating capital goods during a period. Since the question specifies investment during the year, it is measured over time and is therefore a flow variable. Opening and closing capital stock are measured at particular dates and are stocks. Option B is correct.

Correct answer: A. Capital stock

Explanation: The machines, buildings, equipment, and other productive assets existing at a particular point in time together form the country's capital stock. It is a stock because it is measured on a date. Annual investment is a flow that adds to capital stock over a period, so option A is correct.

Correct answer: C. Stock

Explanation: The amount or balance in an account stated for today refers to money existing at a particular point of time. It is therefore a stock variable. The amount deposited over a period, such as all deposits during a month, would be a flow. The key distinction is the point-in-time reference in the question, so option C is correct.

Correct answer: D. Flow

Explanation: The total amount deposited this month is measured over the time interval of one month. Any economic quantity measured during a period is a flow variable. It is different from the account balance at the end of the month, which would be a stock measured at one point in time. Therefore, the correct answer is option D, flow.

Correct answer: A. Wealth and annual income

Explanation: Wealth is the accumulated value of assets owned at a particular point in time, so it is a stock. Annual income is earned over the course of a year, so it is a flow. In the other options, the order is reversed or both terms do not fit the required order. Thus, wealth and annual income correctly represent stock and flow respectively.

Correct answer: B. Exports and foreign exchange reserves

Explanation: Exports are goods or services sold to other countries during a specified period, such as a month or year; therefore, exports are a flow. Foreign exchange reserves are the accumulated stock of foreign currency and related assets held at a particular date. Hence, option B correctly gives flow first and stock second.

Correct answer: B. Population is a stock and births are a flow

Explanation: Population recorded on a fixed date, such as 31 March, measures the number of people existing at one point in time, so it is a stock. Births during a year are counted over an interval of time, so they are a flow. The date-based and year-based wording clearly establishes the distinction, making option B correct.

Correct answer: C. Opening raw material is stock and purchases are flow

Explanation: Opening raw material is the quantity of material available at the beginning of the accounting period, so it is measured at a point in time and is a stock. Raw-material purchases during the year are transactions occurring over a period, so they are a flow. Therefore, option C correctly classifies the two items.

Correct answer: B. Stock

Explanation: A bank loan balance shown in a balance sheet reports the amount still outstanding on a particular reporting date. Since it is measured at that point in time, it is a stock variable. New borrowing or loan repayments made during a year would instead be flows because they are measured over a period. Thus, option B is correct.

Correct answer: C. Flow

Explanation: Annual interest expense represents the interest cost incurred over the complete period of one year. A quantity measured over a period is a flow variable. It should not be confused with the outstanding loan balance at year-end, which is a stock. The word “annual” establishes the time interval, so option C is correct.

Correct answer: A. Flow

Explanation: The amount or rate of water moving through a river per second is measured with reference to a time interval. A quantity measured per second, per day, or per year is a flow variable. A stock would be the total water present in a river, lake, or reservoir at a particular moment. Therefore, option A is correct.

Correct answer: B. Stock

Explanation: The quantity of water stored in a dam at a particular moment is measured at one definite point in time, so it is a stock variable. The water entering or leaving the dam during a day or year would be a flow because it is measured over a period. The phrase “at a moment” makes option B correct.

Correct answer: C. Gross investment is a flow, while capital stock is a stock.

Explanation: Gross investment is a flow because it measures the expenditure on newly produced capital goods during a specified period, such as a month or a year. Capital stock is a stock because it measures the total quantity or value of capital assets available at a particular point in time. Investment during a period can add to the existing capital stock, after allowing for depreciation.

Correct answer: C. Cash available today

Explanation: “Cash available today” identifies a definite point of time: the present day. It describes the amount existing at that moment and therefore represents a stock. Sales during a year, monthly wages, and annual production are measured over periods and are flows. Thus, option C most clearly indicates a point in time.

Correct answer: D. Sales for three months

Explanation: “Sales for three months” explicitly identifies a period lasting three months. Sales occurring throughout that interval are measured as a flow. A debt balance at year-end, assets on a date, and a current bank balance are measured at particular points in time and are stocks. Therefore, option D most clearly indicates a period.

Correct answer: A. Stock

Explanation: The market value of a company stated on a particular date represents the value existing at one specific point in time. Such a quantity is called a stock variable. A flow is measured over a period, such as monthly income or annual expenditure. Therefore, option A is correct.

Correct answer: B. Flow

Explanation: Service income earned during the whole year is measured over a period of time, so it is a flow variable. A flow records an activity or amount accumulated during a specified interval, such as a month or year. In contrast, a stock is measured at one particular point, such as cash held on the last day of the year. Therefore, option B is correct.

Correct answer: C. Stock

Explanation: The value of a financial-asset portfolio at the end of a day is measured at a specific point in time. It is therefore a stock variable. Stocks represent holdings or quantities existing at a particular date, whereas income and expenditure are normally flows measured over an interval. Thus, the portfolio is correctly classified by option C.

Correct answer: D. Flow

Explanation: The total value of shares bought and sold during one day is measured across a time interval, not at a single instant. It is therefore a flow variable. A stock would be the value of shares held at a particular date. The wording “during one day” identifies an activity accumulated over time, so option D is correct.

Correct answer: B. Annual income — stock

Explanation: Annual income is earned and measured over the course of a year, so it is a flow rather than a stock. The other examples are measured at a particular point: cash held today, assets at year-end, and population on a stated date. Since option B wrongly labels a period-based amount as a stock, it is the required answer.

Correct answer: C. Population on the first day of January — flow

Explanation: Population measured on the first day of January is measured at one definite point in time, so it is a stock. It is incorrectly labelled as a flow in option C. Monthly wages, annual output, and exports during a year are measured over periods and are therefore flows. Hence, C is the only incorrect classification.

Correct answer: B. Flow and stock

Explanation: Total consumption expenditure is recorded over a period, such as a month or year, and therefore it is a flow. The value of consumer durables owned by a household is an asset holding measured at a particular point in time, so it is a stock. Consequently, the correct order is flow and stock, given in option B.

Correct answer: A. Cash stock and cash sales flow

Explanation: Cash held at the end of the day is measured at a particular point in time, so it is a stock. Cash sales made during the day are added over an interval, so they are a flow. The words “at the end” indicate a stock balance, while “during the day” indicates a period total. Therefore, option A is correct.

Correct answer: A. Daily wage rate is flow and cash is stock

Explanation: A daily wage rate refers to earnings associated with work over a time period, so wage income is treated as a flow. Cash held at the end of the month is a balance measured at one point in time, making it a stock. The distinction depends on the time dimension: earning during a period is a flow, while an amount held at a date is a stock. Hence A is correct.

Correct answer: B. Stock and flow

Explanation: Natural wealth, such as forests, minerals in the ground, and land, represents resources available at a point in time; it is therefore a stock. Annual mineral production is the quantity extracted during a year, so it is measured over a period and is a flow. Hence the correct order is stock and flow, as stated in option B.