Question 1198354
IF
to be atleast 4 marks 'higher' that his average score for the first 4 exam
(80+79+84+87 )/4 = 82.5
(80+79+84+87+93+x )/6  ≥    86.5
       x  ≥   6*86.5-423  ≥   517-423  ≥     96

  the least score that he must get in the sixth exam is 96