Weighted assignment affecting grade calculator

[Aqtion]

Is your feature request related to a problem? Please describe.
Finding final grade calculators on the internet isn't hard, but when it comes to finding calculators that determine how weighted assignments affect your grade, options are scarce.

Describe the solution you'd like
A simple add-on to the gpa calculator we already have, just further expanding our reach as a grade calculator type website.

[Aqtion]

implementing logic shouldn't be hard, maybe a subsection to this gpac section of the site

[StephenXie]

Yes, the logic of this calculator should be fairly straightforward.

N = Number of graded assignments
A = Average assignment grade
W = Weightage in decimal
S = Score for Assignment

Only one assignment(e.g. final exam, final project, etc.)
Final Grade = Initial Grade*(1-W) + S*W

Multiple assignments
Final Grade = Initial Grade*(1-W) + ((A*N+S)/(N+1))*W