Ihave a 74% in my class and i need a 78% to pass what do i need to get on my final exam?

So the 74% that you have right now is the other 80% of your grade. So you multiply it by its weight and solve for the other one making it equal to 78%.

(.74)(.8) + (.2)(x) = .78
 .592 + (.2)(x) = .78
    (.2)(x) = .188
       (x) = .94

So, you need to get a 94% on your final test.

That they are numbers and related to each other.