18. a student scored 78 and 95 on his first two quizzes. use a compound inequality to find the possible values for a third quiz score that would give him an average between 80 and 90, inclusive. (1 point)67 ≤ x ≤ 9778 ≤ x ≤ 9580 ≤ x ≤ 9086 ≤ x ≤ 87

The answer to this item could be identified by assigning x as the third number and equating the average of the scores as 80 or 90.

 80:
 
    80 = (78 + 95 + x)/3
The value of x from the equation is equal to 67. 

90:
   
   90 = (78 + 95 + x) / 3
The value of x from the equation is equal to 97.

Thus, the score should be 67 ≤ x ≤ 97.

The answer is the first choice. 

For being nice i appreciate it but abc