Question 28653
(2/3)64+(1/3)X=70 TO 79

128/3+X/3=70 TO 79

(128+X)/3=70 TO 79

128+X=210 OR 237

X=210-128 OR 82 & X=237-128 OR X=109 THEREFORE TO AVERAGE BETWEEN 70 & 79 
THE FINAL TEST SCORE NEEDS TO BE BETWEEN 82 & 100.