JAMB Economics 2022
Questions & Answers

One might mistakenly choose option A or B by assuming an economy must rely entirely on either the state or the free market. A mixed economy combines government intervention and market forces to allocate resources, balancing central planning with supply and demand. Common mistake: Believing a mixed economy operates under exclusively single-source decision making.

A student could select option B or D by confusing market systems with command economies. Consumer demand and preferences guide firms on what to produce in a market economy, as firms aim to meet market needs to maximize profits. Common mistake: Attributing market economy decisions to government directives instead of consumer choices.

A student might select option B by confusing standard deviation with variance, or choose option A by focusing on extreme values. Mean deviation measures the average absolute deviation of data points from the mean, providing a straightforward measure of dispersion. Common mistake: Confusing mean deviation with variance or range.

One might mistakenly pick option B or D by multiplying the variance or misunderstanding the formula relationship. Standard deviation is the square root of variance: √16 = 4. Common mistake: Forgetting to take the square root of the variance.

A student might choose option A or C by selecting factors that increase rather than decrease supply. Higher input prices increase production costs, reducing supply and shifting the supply curve leftward. Common mistake: Confusing the effects of rising input costs with falling production costs on supply shifts.

A student might make a calculation error while solving for price and substituting it back into the equations. Set Qd = Qs: 50 - 3P = 5P + 10. Solve: 50 - 10 = 5P + 3P, 40 = 8P, P = 5. Substitute P = 5 into Qs: Q = 5(5) + 10 = 30. Common mistake: Algebraic errors when isolating the price variable during equilibrium calculation.

One might pick option A or D by selecting determinants that cause an entire curve shift instead of a point movement. A change in the price of the commodity causes a movement along the demand curve, reflecting a change in quantity demanded. Common mistake: Confusing a shift of the demand curve with a movement along the curve.

A student could choose option A by inverting the numerator and denominator in the formula. Price elasticity of demand = (% change in quantity demanded) / (% change in price) = 10% / 5% = 2.0, indicating elastic demand. Common mistake: Putting price percentage change in the numerator instead of the denominator.

One might select option A or C by incorrectly linking utility changes to price tags or income instead of consumption volume. The law of diminishing marginal utility states that as more units of a commodity are consumed, the additional satisfaction (utility) derived from each extra unit decreases. Common mistake: Confusing changes in consumption quantity with external market price changes.

A student might incorrectly choose an increase in income, thinking it reduces capability, but purchasing power diminishes when funds drop, causing fewer goods to be attainable and drawing the boundary inward. Common mistake: confusing an outward shift from rising wealth with the inward contraction caused by a drop in funds.

One might mistakenly calculate using incorrect algebra or pick an option like 80 by misplacing the values. To find the quantity, substitute twelve for P to get twelve equals one-fifth of the sum of Qs and twenty. Multiply both sides by five to arrive at sixty equals Qs plus twenty, then subtract twenty to find forty. Common mistake: failing to multiply the entire equation by five before isolating the unknown.

A student might guess forty percent by simply adding or doubling the numbers without proper division. To find the unknown, determine the percentage change in quantity supplied by finding the difference between one hundred thirty and one hundred, which is thirty percent. Since elasticity equals one point five, divide thirty percent by one point five to arrive at twenty percent. Common mistake: dividing the elasticity value by the quantity change instead of the other way around.

A student might mistakenly select excess supply or excess demand, confusing ceilings with floors. Because the limit is placed above the point where supply meets demand, it has no impact since the market naturally settles at equilibrium. Common mistake: assuming any government price rule automatically creates a market shortage or surplus.

A student might incorrectly select a mixed economy, assuming state involvement halts all price movements entirely. In a command economy, however, the government dictates all values instead of letting market forces operate, rendering prices ineffective as signals. Common mistake: confusing government regulation in mixed systems with absolute state price-fixing.

A student might mistakenly choose forty-five by adding only a portion of the values or multiplying instead of adding. Total output when employing six units equals the previous output plus the marginal product, which is forty plus ten, giving fifty. Common mistake: treating marginal product as the new total rather than adding it to the prior total.

A student might mistakenly select rising average cost, confusing economies with diseconomies of scale. Efficiencies such as bulk purchasing and worker specialization cause average costs to drop as total output expands. Common mistake: mixing up long-run cost reductions with diminishing returns.

A student might incorrectly pick reduced efficiency, assuming specialization creates bottlenecks rather than gains. While output per worker rises, it creates deep interdependence because workers and firms must rely on each other for different tasks and goods. Common mistake: assuming higher efficiency means complete self-sufficiency.

A student might guess a different figure by multiplying the numbers instead of dividing. Average variable cost is found by taking the total variable cost of one thousand five hundred and dividing it by the output of fifty units to get thirty. Common mistake: multiplying total variable cost by output instead of dividing.

A student might mistakenly choose fixed costs, thinking bills remain constant every month. Wages and raw materials fluctuate based on production volume, making them variable, whereas fixed costs stay level regardless of output levels. Common mistake: assuming all business expenditures remain unchanged in the short run.

A student might mistakenly select total revenue equaling total cost, which defines break-even rather than optimal production. Profit reaches its peak where marginal revenue equals marginal cost, guaranteeing that the extra expense of creating one more item matches the extra revenue collected. Common mistake: confusing profit maximization with the break-even point.