Question 936883
if all tests have the same weight, then you would calculate as follows.


to get an overall average of 75 over 8 tests, then you would have to have a total of 8 * 75 = 600 points.


this is because 600 / 8 equals an average of 75 per test.


you already have a total of 504 points because 7 * 72 = 504.


you would need an additional 96 points in order to get a total of 600 points for the 8 tests.


that's the mark you will need on the eighth test.


look at it another way.


if you had a 75 average on the first 7 tests, then your total score for the first 7 test would have been 7 * 75 = 525.


since you only had 504, you were short 21 points.


on the last test, you need to get a 75 plus you have to make up for the shortfall from the first 7 test.


75 + 21 = 96.


any way you look at it, you would need a 96 on the last test to get an overall average of 75 on your tests.


average = total / number of tests.


total = average * number of tests.