How do you figure out what you need to get on a final to earn a certain grade?

Chuck be has got it. Here is how I figure it out, slightly differently and maybe easier to understand.





Let's say you currently have 75% from everything before the final, and you want to get 90% in the class for a final grade of A-. Let's also say that the final is worth 20% of your grade, and therefore everything before is 80% of your grade.





0.8*75 + 0.2*F = 90





F is the grade on the final, and in this case, solving for F gives you 150, and unless there is massive extra credit on the test this means that an A- is impossible.





Let's see the highest possible grade you can get, if you get 100 on the final.





0.8*75 + 0.2*100 = 80





So if you have 75% going into the final, the highest grade you can possibly get is 80, a B- in an unweighted system. If grades are weighted it is impossible to do this calculation because your grade depends on how everyone else does as well.How do you figure out what you need to get on a final to earn a certain grade?
Two intelligent solutions have been given. Choose either one./ I prefer the second.How do you figure out what you need to get on a final to earn a certain grade?
You would have to know 3 things:


A) The weighting of the final exam.


B) The current grade average


C) The desired final grade average.





Let's say, for instance that you are currently carrying an 80% average (item B = 80%). Let's say that the final exam counts for 25% of your final grade (item A = 25%). And, finally, let's say that you want to have an 85% average after the final exam (item C = 85%).





Use the following formula:





(A / 100)x + (((100 - A) / 100)B) = C





so, using the values above:





(25 / 100)x + (((100 - 25) / 100)80) = 85


.25x + ((75 / 100)80) = 85


.25x + (.75(80)) = 85


.25x + 60 = 85


.25x = 25


x = 100





So, you would have to have a 100% on your final exam to end up with a course average of 85%.





Hope this helps.

hack myspace