Science asap!!!
posted by HS .
This question is about energy efficiency.
e.g.
more efficient
A=
B
C
D
E
Less Efficient
my question
An old freezer has an energy consumption per year of 350kwh
use the equation in the box to calculate the extra cost of using the old freezer for one year compared with using a new A rated freezer.
total cost= number of kilowatthours x cost per kilowatthour
show clearly how you work out you answer

Surely you were given the consumption for the A rated freezer. Cost is immaterail, it is the same per kilowatt hour for each. So you are just comparing the kwh consumption for each. So what is it?
Then, second problem, say you find out the consumption is 267kwh/year. So you know the old freezer takes more, so it is less efficient. But exactly where on that silly scale does it go? Is it B, C, D, E?
If this is all your teacher gave you, you cannot possibly answer it. It reminds me of a beauty contest: how do you rate beauty? A, B, C, D, E, or F?
Goodness, your teacher could have done a better job than this....or, you have other information here that you have not shared. Ask your parents to assist. 
sorry I forgot to say
that we should assume 1 kilowatthour (kwh) of energy cost 12p
i'm from the uk so we use the letters to see how efficient something is
i'm not sure what your trying to say...