Question 11- is 10
question 12- is 36
Question 15- is 58
Answer:
116 students
Step-by-step explanation:
The standard deviation for a proportion is:

For any measured sample proportion x, the z score is given by:

The population proportion is 0.53
At the 14th percentile, the corresponding z-score is z =-1.08.
Since 0.48 is at the 14th percentile, the standard deviation is:

Therefore, the sample size 'n' is given by:

The sample size must have been of 116 students.
In equations like this, you could use PEMDAS- Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction in that order. Since there are no parentheses or exponents you can go to multiplication. Since x=9 and y=6, you multiply x(9) and y(6) to get 54. Now you can add since there is no division or subtraction involved. 54+ u(2) = 56. So u + xy = B. 56
You were probably given a number to plug into the equation , which is no different then it being y=x-4 , just solve for the f(x)