When the market price is set above the equilibrium level, the quantity supplied by producers exceeds the quantity demanded by consumers, creating a surplus. This excess supply exerts downward pressure on the price, causing it to fall until it reaches the equilibrium point where the market clears.

For a non-smoker, the quantity demanded for cigarettes is zero regardless of the price level. Since the quantity demanded does not change even if the price changes (it remains at zero), the demand is perfectly price inelastic. The coefficient of price elasticity of demand is zero in this case, indicating that price fluctuations have no impact on the consumption behavior of this specific individual.

An inferior good is defined as a good for which demand declines as consumer income rises. This typically happens because consumers switch to higher-quality or more expensive alternatives as their purchasing power increases, making the original good less desirable.

If the proportion of income spent on a good remains constant regardless of income level, the percentage change in expenditure is equal to the percentage change in income. Mathematically, if Expenditure = k * Income, then a 1% increase in income leads to a 1% increase in expenditure. Since expenditure is Price * Quantity, and price is constant, quantity must also increase by 1%. Thus, the income elasticity of demand is 1.00. Note: The provided answer 'D' appears to be a typo for 1.00.

On a linear demand curve, the slope is constant, but the ratio of price to quantity changes. At higher prices (upper portion), a small absolute change in price represents a small percentage change, while the resulting quantity change is a large percentage change, leading to elasticity greater than one. Conversely, at lower prices (lower portion), the percentage change in quantity is smaller relative to the percentage change in price, resulting in inelastic demand.

When production costs rise, the marginal cost of producing each additional unit increases. Consequently, producers are willing to supply less at any given price level. This results in a leftward or inward shift of the supply curve, reflecting a decrease in supply due to higher input prices or operational expenses.

Unit elastic demand occurs when the price elasticity of demand is exactly equal to 1. In this scenario, the percentage change in quantity demanded is exactly proportional to the percentage change in price. Consequently, any change in price is perfectly offset by the change in quantity, resulting in total revenue remaining constant regardless of the price adjustment.

A price elasticity of -0.3 indicates that demand is price inelastic (the absolute value is less than 1). The provided answer 'Demand is upward sloping' is factually incorrect, as demand curves are typically downward sloping. This conflict suggests the source key is misinterpreting the mathematical value of elasticity or the fundamental law of demand.

Cross-price elasticity is calculated as the percentage change in quantity demanded of one good divided by the percentage change in the price of another. Here, 5% divided by 20% equals 0.25. A positive value indicates that beef and chicken are substitute goods.

Price elasticity of supply is calculated as the percentage change in quantity supplied divided by the percentage change in price. The percentage change in quantity is (4/40) = 10%. The percentage change in price is (5/25) = 20%. Dividing 10% by 20% yields an elasticity coefficient of 0.5. This indicates that the supply is relatively inelastic, as the percentage change in quantity is less than the percentage change in price.