How to calculate a percentage of something?

Let's say my mark in Math atm is 55%. My final exam is worth 30% of my mark.



If I were to get a 45% on this exam,what would that make my final mark?

If I were to get a 55% on this exam, what would my final mark be?



How is this calculated?How to calculate a percentage of something?
OK, so you know 55 is 70 percent of your total grade.



If you get a 45 on the final, that is 30 percent of your total grade.



So add (55 times 7) plus (45 times 3) and then divide by 10 to get your total.



For the second question, it would just be (55 times 7) plus (55 times 3) although you can tell just by LOOKING at this one that your final grade would be 55.