SOLUTION: Rachel hands in her 4th exam. the scores on her first three examns were 75,95,97.what foes she need to earn on the 4th exam to average at least a 90 on the four exams. contruct an

Algebra ->  Expressions-with-variables -> SOLUTION: Rachel hands in her 4th exam. the scores on her first three examns were 75,95,97.what foes she need to earn on the 4th exam to average at least a 90 on the four exams. contruct an      Log On


   

Question 202514: Rachel hands in her 4th exam. the scores on her first three examns were 75,95,97.what foes she need to earn on the 4th exam to average at least a 90 on the four exams. contruct an inequality with the variable x representing the 4th score, the salvge the inquality for x.
Found 2 solutions by rfer, MathTherapy:
Answer by rfer(16322) About Me  (Show Source):
You can put this solution on YOUR website!
75+95+97+x=267
267x/4=67

Answer by MathTherapy(10557) About Me  (Show Source):
You can put this solution on YOUR website!
Since Rachel needs to get AT LEAST a 90-average on the four exams, using the average formula, which states:

%28sum+of+scores%29%2F%28number+of+scores%29+=+Average, we then get the following inequality:

%2875%2B95%2B97%2Bx%29%2F4%3E=90

Multiplying each expression by the LCD, 4, we get: 267+%2B+x%3E=360, or x%3E=93

Therefore, in order for Rachel to average at least a 90 on all four exams, she has to score a 93, or more on her 4th and final exam.

Check
%2875+%2B+95+%2B+97+%2B+93%29%2F4+%3E=+90

360%2F4%3E=90

90%3E=90