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Jackie scored 82 and 88 on her first two quizzes. Write and solve a compound inequality to find possible values for a third quiz score that would give her an average between 80 and 85, inclusive.

a. 80 <= 82 + 88 + n / 3 <= 85; 70 <= n <= 85

b. 70 <= 82 + 88 + n / 3 <= 85; 80 <= n <= 85

c. 80 <= 82 + 88 + n / 3 < 85; 70 < n < 85

d. 82 <= 80 + 85 + n / 3 <= 88; 70 <= n <= 85

Respuesta :

pegah
the answer is a . first you can understand that b and d can not be the answers because the question says that hey score should be between 80 and 85 so between a and c the answer is a :)))
i hope this is helpful 

Answer : option A

Jackie scored 82 and 88 on her first two quizzes

Let n be the score of third quiz

Average of 3 quiz = [tex]\frac{82+88+n}{3}[/tex]

average between 80 and 85, inclusive.

so average lies between 80  and 85

Question says 80  and 85 inclusive. so we use <= or >= symbol

So inequality becomes

[tex]80<= \frac{82+88+n}{3} <= 85[/tex]

[tex]80<= \frac{170+n}{3} <= 85[/tex] ( multiply all sides by 3)

[tex]240<=170+n<= 255[/tex] (subtract all sides by 170)

[tex]70<=+n<= 85[/tex]

so option A is correct