Answer:
C
Step-by-step explanation:
Finding the z-score:
z = (x - μ) / σ
z = (66 - 57) / 9
z = 1
Using a z-score table or calculator:
P(z < 1) = 0.8413
84.13% of 4000 is:
0.8413 (4000) = 3365.2
Rounding up to the nearest whole number, approximately 3366 students will score less than 66. Answer C.
2/3 is just .6666666666 and the 6 goes on forever
Answer:
Sandra need to score at least <u>56%</u> in her fifth test so that her average is 80%.
Step-by-step explanation:
Given:
First 4 test scores = 87%, 92%, 76%,89%
Average targeted = 80%
We need to find the minimum score she needs to make on fifth test to achieve average of at least 80%.
Solution:
Let the minimum score she needs to make in fifth test be 'x'.
Total number of test = 5
Now we know that;
Average is equal to sum of all the scores in the test divided by number of test.
framing in equation form we get;

Multiplying both side by 5 we get;

Subtracting both side by 344 we get;

Hence Sandra need to score at least <u>56%</u> in her fifth test so that her average is 80%.
The complete answer is 2.25E-17
but I think it may be A