Answer:
<m is equal to the measure of <Z
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The answer is 11 degrees if you want to know why this is the answer reply to my comment
Let
be the random variable for the number of marks a given student receives on the exam.
10% of students obtain more than 75 marks, so

where
follows a standard normal distribution. The critical value for an upper-tail probability of 10% is

where
denotes the CDF of
, and
denotes the inverse CDF. We have

Similarly, because 20% of students obtain less than 40 marks, we have

so that

Then
are such that


and we find

B is the answer I think.Please make me brainlist answer!