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.

A80 <= 82 + 88 + n / 3 <= 85; 70 <= n <= 85

B70 <= 82 + 88 + n / 3 <= 85; 80 <= n <= 85

C80 <= 82 + 88 + n / 3 < 85; 70 < n < 85

D82 <= 80 + 85 + n / 3 <= 88; 70 <= n <= 85

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

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lisboa lisboa · Answer 2 · 2018-09-10T20:33:10-04:00

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 = \(\frac{82+88+n}{3}\)

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

\(80<= \frac{82+88+n}{3} <= 85\)

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

\(240<=170+n<= 255\) (subtract all sides by 170)

\(70<=+n<= 85\)

so option A is correct