Question 684279
(78+68+71+85+90+X)/6>=80
(392+X)/6>=80 CROSS MULTIPLY
392+X=6*80
392+X=480
X=480-392
X=88 ANS, FOR THE MINIMUM SCORE TO MAINTAIN AN 80 AVERAGE OR GREATER.
PROOF:
(392+88)/6=80
480/6=80
480=6*80
480=480