Answer:
900 sample size
Step-by-step explanation:
To determine the sample size for a proportion, the margin of error formula is used to determine this:


Where p is the proportion, E is the margin of error, n is the sample size, q = 1 - p,
is the z score.
Since the proportion is not known, the sample size needed to guarantee the confidence interval and error is at p = 0.5 and q = 1 - p = 1 - 0.5 = 0.5
E = 5% = 0.05,
= 3. Hence:

You are 11 because the age to enter highschool is 16 - 5=11
I would divide 120 by 6 and get 20
Answer: OPTION D: 
Step-by-step explanation:
By definiton, fractions have the following form:

Where "a" is called numerator and "b" is the denominator. The numerator and the denominator are Integers.
In order to solve this exercise you need to remember de Division of fractions:

In this case, according to the information given in the exercise, you know that
of rubies are divided into 4 lots.
Therefore, in order to calculate the weight in pounds of each lot, you need to divide
by 4.
Then, you get the following result:

As you can notice, this result matches with the Option D.
The solution to x + 8.5 = 64.5 is 56.
x + 8.5 = 64.5
- 8.5 - 8.5
---------------------------
x = 56