Question 363113
(88+72+85+76+x)/5>83
(321+x)/5>83
321+x>5*83
321+x>415 
x>415-321
x>94 is the minimum score on the last test to maintain an 83 average.
Proof:
(88+72+85+76+94)/5=83
415/5=83
83=83