In this case, your weights add up to 1.75, or 175%. To find your score, first add up the individual scores multiplied by their weights: 50(.5) + 70(.5) + 100(.25) + 100(.25) + 7(.25) = 111.75. Then, divide the result by the total weight: 111.75/1.75 = 63.86. This means your grade average in the class is 63.86, which you can round up to 64.