Problema Solution

AMATH STUDENT EARNED SCORES OF 96,92,78 AND 88 ON THE FIRST FOUR EXAMS. WHAT MUST HE EARN ON EXAM 5 TO HAVE AN AVERAGE OF EXACTLY 90.

Answer provided by our tutors

five exams scores must average to exactly 90 and we

  know four of the scores: 96, 92, 78 and 88

the final average is represented by this equation

  (allowing the 5th score to be given as 'x'):

  (96 + 92 + 78 + 88 + x)/5 = 90

solving for x, we have:

  (354 + x) = 450

  x = 450 - 354 = 96

the student must score a 96 on the 5th exam in order to earn an average of exactly 90