The student would have to score 100% on their next test to brung their average up to 90. Here is why;
90+84+86=260
(260+?)/4=90
(260+100)/4=90
360/4=90
This is done to get the mean (or average) of a group of numbers by adding all the numbers and dividing by the amount of numbers you added together. Here it is divided by 4 because of the three tests he has taken and the test he will take.
We are looking to find P(X>60 students)
X is normally distributed with mean 50 and standard deviation 5
We need to find the z-score of 60 students

To find the probability of P(Z>2), we can do 1 - P(Z<2)
So we read the probability when Z<2 which is 0.9772, then subtract from one we get 0.0228
The number of students that has score more than 60 is 0.0228 x 1000 = 228 students
Answer:
16 is H.9
17. is A.9
Step-by-step explanation:
Hope it helped! ^_^
Answer:
What grade is this
Step-by-step explanation:
I can give you the answer but you have to be patient like 30 min