How do you calculate your final grade based on your test scores & what they're worth?

Like if your current grade is 80% in a class, and you get 60% on an assignment that's worth 30% of your final grade, what will your final grade change to?How do you calculate your final grade based on your test scores %26amp; what they're worth?
74 percent is your new grade. To do it a simple way, think of your entire grade as the sum of ten parts. 3 of those parts are worth 60 (so a total of 180) and 7 of those parts are worth 80 ( so a total of 560). Now add those together to get your 10 parts ( 180 + 560 = 740). Then divide 740 by ten to give you the percentage.