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
I think it's C but I might not be right
Answer:
4
Step-by-step explanation:
Answer:
4.624e+15
Step-by-step explanation:
I think this is the correct answer may be wrong
The answer would be 60. By rounding, 14.2=14; 15.51=16; 14.99=15; 15.8=16.
14+15+16+16=61
Rounding: 61=60