Question

an electric company charges a certain rate per kilowatt - hour (kwh) of electricity used and an administrative fee of $3.50. the company charged zhao $63.25 for using 800 kwh of electricity. zhao uses the equation, 63.25 = 800r + 3.50 to represent the situation. what does the variable r represent in the equation? choose 1 answer: a the number of kilowatt - hours zhao used b the charge per kilowatt - hour c the amount of the total charge that depends on the number of kilowatt - hours used

Explanation:

The equation given is \( 63.25 = 800r + 3.50 \). We know that the total charge (\( \$63.25 \)) is the sum of the cost for the electricity used and the administrative fee (\( \$3.50 \)). The cost for electricity used should be the rate per kilowatt - hour (\( r \)) multiplied by the number of kilowatt - hours used (800 kWh).

• Option A: The number of kilowatt - hours used is 800, not \( r \), so A is incorrect.
• Option B: Since the cost for electricity is \( 800r \) (number of kWh times rate per kWh) and the total cost is \( 800r+3.50 \), \( r \) must represent the charge per kilowatt - hour. This makes sense.
• Option C: The total charge is \( 63.25 \), not \( r \), so C is incorrect.

Answer:

B. The charge per kilowatt - hour