I'm trying to take a list of grades and calculate what I would need to get on a test in-order to get an "A". I'm just having trouble with the equation.

var HW1=95;
var HW2=0;
var HW3=100;
var HW4=100;
var MT=100;
var Final;
var PointsPossible=600;

document.write(Final)

This is about all I have. Like I said, I need to take the grades and figure out what I need on the Final to get an "A" (>=90). I'm just completely lost on how to set up the equation and if I need any more variables or information.

Can anybody help me out?

isnt this just some simple math?

Final=(HW1+HW2+HW3+HW4+MT)/PointsPossible
if(Final>=90){ you get an A }

btw, does a MT count 2x? if so you need to do:
Final=(HW1+HW2+HW3+HW4+(MT*2))/PointsPossible