I think it the answer is A
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
Answer:
-57
Step-by-step explanation:
256=199-j
256-199=57
Answer:
A
Step-by-step explanation:
A is the answer because it gives direct address to parents and kids. All the others don't give a direct subject, unlike A that says parents and kids.
Answer:
3 pounds
Step-by-step explanation:
