Question

On the last three physics exams a student scored 89, 87, and 92. What score must the student earn on the next exam to have an average above 90?
Lots represent the score the student must eam What is this score?
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(Simplify your answer. Type an intogor or a decimal)

Answer 1

Answer:

For the average to be above 90, the marks in the fourth paper should be MORE THAN 92.

Step-by-step explanation:

The score of students in last 3 exams =  89 , 87 and 92

Let us assume the marks scored by the student in last exam = k

The average of marks should be above 90.

Now, $\textrm{The average of total marks} = \frac{\textrm{Sum of all marks obtained in 4 papers}}{\textrm{ 4 papers }}$

Sum of all 4 paper's marks =  89 + 87 + 92 + k = 268 + k

Also, 90 <  Average

$\implies 90 < \frac{268 + k}{4}\\ or, 360 < 268 + k\\\implies 360 - 268 < k\\or, k > 92$

Hence,for the average to be above 90, the marks in the fourth paper should be MORE THAN 92.