 OK, here we are trying to compare two air conditioners, both of which are going to last 10 years. One consumes less power and the other one, high power. They both operate for 2,400 hours annually. So we have the power and we have the time of usage data. So we need to calculate how much energy each of these will consume. So life of one or first air conditioner is 10 years and second one is 10 years. Power is 775 least efficient watts and the other one is 700 watts. We have the time of usage. Time of usage is given as 2,400 hours and this one is also 2,400 hours. Now so the energy consumed is given by power multiplied by time of usage. So in this case it would be 775 watts multiplied by 2400 hours and that will be 1,860,000 watt hours. And for this air conditioner it would be 700 watts times 2400 hours. That will be 1,680,000 watt hours. So we need to convert this into kilowatt hours because we buy by kilowatt hours. So dividing it by 1,000 and dividing here by 1,000 we get kilowatt hours. So this air conditioner will consume 1,860 kilowatt hours per year. This one would consume 1,680 kilowatt hours per year. So in 10 years the energy consumption is 18,600 kilowatt hours. This is simply multiplying yearly consumption by 10 years. And for the least efficient one it would be 1,680 multiplied by 10. That would be 16,800 kilowatt hours. We know the price of each of these, you know, each of the kilowatt hours. That is, it is so the rate of 0.8 dollars per kilowatt hour. So when you multiply that by 0.8 both sides the cost to operate this one would be 1,488 dollars and this one would be 1,344 dollars. So the difference is 1,444 dollars. Which means the least efficient one basically costs 144 dollars one, 144 dollars more. And the best one would be actually even if it is priced 144 dollars more it would work out to be the same amount in a long run over 10 years. But we will be helping the environment by not burning, you know, the difference between these two kilowatt hours and a couple of thousand kilowatt hours over 10 years. That would be the help for the environment.