Answer:
a. 4.33.
Step-by-step explanation:
If there is only one correct answer out of four alternatives, the expected proportion of correct answers is p =0.25
Sample size (n) = 100 questions
The standard deviation of a proportion 'p' is given by:

Applying the given data:

If X is the number of correct responses in 100 guesses, the standard deviation of X is:

The standard deviation of X is 4.33 questions.
(y -3)^2 = 4y - 12
Expand.
(y-3)(y -3) = 4y - 12
y² - 6y + 9 = 4y - 12
y² - 6y -4y + 9 + 12 = 0
y² - 10y + 21 = 0
Factors are -7y and - 3y
y² - 10y + 21 = 0
y² - 3y - 7y + 21 = 0
y(y - 3) -7(y - 3) = 0
(y - 3)(y - 7) = 0
y-3 = 0 or y - 7 = 0
y = 0 + 3 or y = 0 + 7
y = 3 or 7
Integer
because step-by-step-equation
Answer:
6
Step-by-step explanation:
We know that the area of a circle is equal to 
.
A semi-circle is a half-circle, meaning that it will have half of the area of a full circle.
Therefore, a semi-circle's area is equivalent to
.
Set this equation equal to 18
.
Solve for r.
We then find that r = 6.
Now, we need to find the circumference. We know that the equation for the circumference of a circle is 2
r. Since we only need the perimeter of half of a circle, our circumference equation will equal
r.
Plug 6 in for r.
The perimeter of the garden is equal to 6
.