Energy consumption and cost calculation Steps:

• Convert time to decimal hours: 2 hours + 30/60 hours = 2.5 hours.
• Compute energy used: energy (kWh) = power (kW) × time (h) = 3.0 × 2.5 = 7.5 kWh.
• Compute total cost: cost = energy × rate = 7.5 kWh × 20 c/kWh = 150 c. Why none of the options is correct:
• The standard formula for electrical cost is rate × power × time (in hours), yielding 150 c here. Why the others are wrong:
• A. 16c assumes only ~16 min of use (0.8 kWh).
• B. 17c assumes only ~17 min of use (0.85 kWh).
• C. 40c assumes only ~40 min of use (2 kWh).
• D. 48c assumes only ~48 min of use (2.4 kWh).

Final answer: None of the options