Test: Utility Bills - Commerce MCQ

The percentage increase in Rahul's electricity bill from January to February can be calculated using the formula:
Percentage Increase = ((New Value - Old Value) / Old Value) × 100%
Substituting the given values:
Percentage Increase = ((150 - 120) / 120) × 100% = (30 / 120) × 100% = 25%

To find the percentage decrease, use the formula:
Percentage Decrease = (Original Amount - New Amount) / Original Amount × 100
Here, the original amount (March) = Rs. 80 and the new amount (April) = Rs. 65.
Percentage Decrease = (80 - 65) / 80 × 100 = 15 / 80 × 100 = 18.75%

Ajay's gas bill increased by 10% in January. To find his gas bill in January, we can calculate the increase as follows:
Increase = Old Value × (Percentage Increase / 100) = 90 × (10 / 100) = Rs. 9
So, the gas bill in January was Rs. 90 (old) + Rs. 9 (increase) = Rs. 99.

Deepika's internet bill increased by 25% in July. Using the same formula as question 1, we find the new bill amount.

Rohan's phone bill decreased by 20% in October. Using the same formula as question 1, we find the new bill amount.

Neha's electricity bill decreased by 15% in December. Using the same formula as question 1, we find the new bill amount.

Ankit's water bill decreased by 10% in June. Using the same formula as question 1, we find the new bill amount.

Pooja's gas bill increased by 20% in September. Using the same formula as question 1, we find the new bill amount.

Vivek's Internet Bill Calculation
Original Bill in February: Rs. 80
Percentage Decrease: 12.5%
Calculation:

• Decrease = (12.5 / 100) × 80 = Rs. 10
• March Bill = 80 - 10 = Rs. 70

Vivek's Internet Bill in March: Rs. 70

Sunita's phone bill increased by 30% in May. Using the same formula as question 1, we find the new bill amount.

The law of diminishing marginal utility states that as a person consumes more units of a good or service, the additional satisfaction or utility derived from each additional unit decreases. This means that the marginal utility decreases as consumption increases.

The equimarginal principle states that a consumer maximizes utility when the marginal utility per dollar spent (or price) is equal across all goods and services. This means that the consumer allocates their budget in such a way that the ratio of marginal utility to price is the same for all goods consumed.

When consuming an additional unit of a good leads to a decrease in total utility, it implies that the marginal utility of that additional unit is negative. This means that the satisfaction or utility derived from consuming that additional unit is less than the satisfaction from consuming the previous unit.

The equimarginal principle states that a consumer maximizes utility when the ratio of marginal utility to price is equal for all goods consumed. This is represented by option A, where MUᵢ represents the marginal utility of the i-th good and Pᵢ represents the price of the i-th good.

Total utility (TU) is the sum of the utilities (U) derived from consuming each unit of a good or service. This formula adds up the utility obtained from each individual unit consumed, resulting in the total utility derived from consuming all units.