The product of 5 and x squared — 5(x)^2
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

M=2,000÷((1−(1+0.072÷12)^(−12
×2))÷(0.072÷12))
M=89.73
Let
S------> The sum of the measures of the interior angles of a polygon
n-------> number of sides of a polygon
we know that
The formula to find the sum of the measures of the interior angles of a polygon is equal to
°
in this problem
°
Solve for n

therefore
the answer is
