270 dollars
Step-by-step explanation:
He's going to watch 90 hours of tv in 30 days, so multiply 90 hours x 250 watts, Which is 22500 watts over 30 days, then convert to kilowatts which would be 22.5 kilowatts total. He used .25 kilowatts an hour every day. Then multiple 22.5 x 12 cents to get your answer 270. He paid 270 dollars for electricity for the tv.