I have two questions that i need help with, plz? 1) A 9V battery costs $1.49 and will run a portable CD player for 6 hours. Suppose the battery supplies a current of 25mA to the player. What is the cost of energy in dollars per kWh? I started out using ohms law but am lost for there. How do i set up this for a formula i can solve for dollars per kWh? 2) The monthly(30days) electric bill included the cost of running a AC unit for 2hr/day at 5000W, and a series connection of ten 60W lightbulbs for 5hr/day. How much did these items contribute to the cost of the monthly electric bill if electricity costs 8.0 per kWh? 1st i added the ten 60W = 600W. Next, i took (2hr/d)*(30d) = 60h. Also took (5hr/d)*(30d)=150h, i added 5KW + 600W = 5.6KW for total wattage. I plugged in a formula like so (5.6k)*(2.1k)* ??? How do i find the daily cost of electricity, my answer is 2.86x10^-1, i got that from (8/kWh) / 4weeks = ans. Then ans / 7 days = 2.86 x 10^-1 But i am not right, what am i doing wrong, can you help me solve this plz?