Question 953500
With a mean of 78.5 after 6 exams, the sum of his exam scores is (6)(78.5)=471. To average 80 over 7 exams, the sum of scores must be (7)(80)=560. On the final test, he must score 560-471=89. He must score a minimum of 89 to have an overall mean 0f 80.