Kim's TV uses 125 watts of electricity per hour. She runs it for 4 hours a day. If electricity cost 14 cents per kw/h how many cents does her TV cost to run for a week? Give me reasons, before answering the question
She uses 4 hours / day * 125 watts / hour = 500 watt hours / day. That means she uses 500 watt hours / day * 7 days / week = 3500 watt hours / week. This is 3500 watt hours / 1000 watts / kw = 3.5 kw hours. So her TV cost 3.5 kw hours / week * $0.14 / kw hour = $0.49 / week. So the final answer is 49.