Question

William got scores of q sub 1, , and q sub 3 on three quizzes.

a. Write a formula for the average x of all three quizzes.


b. William got an 85 and an 88 on the first two quizzes. What formula can William use to determine the score he needs on the third quiz to get an average of 90? What score does he need?

Answer 1

a. The average is =(++) .

b. He can use the formula =−− q sub 3 , equals 3 x minus , q sub 1 , minus , q sub 2. He will need a score of =()−−= q sub 3 , equals 3 open 90 close minus 85 minus 88 equals 97 on his third quiz.

Explanation: