Answer:
Stratified sampling
Step-by-step explanation:
Samples may be classified as:
Convenient: Sample drawn from a conveniently available pool.
Random: Basically, put all the options into a hat and drawn some of them.
Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.
Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.
Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.
In this question:
Population divided into groups, and random samples are drawn from the groups. This is a mark of stratified sampling.
First translate the English phrase "Four times the sum of a number and 15 is at least 120" into a mathematical inequality.
"Four times..." means we're multiplying something by 4.
"... the sum of a number and 15..." means we're adding an unknown and 15 and then multiplying the result by 4.
"... is at least 120" means when we substitute the unknown for a value, in order for that value to be in the solution set, it can only be less than or equal to 120.
So, the resulting inequality is 4(x + 15) ≤ 120.
Simplify the inequality.
4(x + 15) ≤ 120
4x + 60 ≤ 120 <-- Using the distributive property
4x ≤ 60 <-- Subtract both sides by 60
x ≤ 15 <-- Divide both sides by 4
Now that we have the inequality in a simplified form, we can easily see that in order to be in the solution set, the variable x can be no bigger than 15.
In interval notation it would look something like this:
[15, ∞)
In set builder notation it would look something like this:
{x | x ∈ R, x ≤ 15}
It is read as "the set of all x, such that x is a member of the real numbers and x is less than or equal to 15".
Answer:
the answer is C. 210 sq. cm
Step-by-step explanation:
Find the area of the triangle
The area of one of the triangular faces can be found by using the formula below.
a = 1/2 bh
a = 1/2 (5 cm) (12 cm)
a = 30 sq. cm
Since there are two triangular faces, multiply the area of one triangular face by 2. The area of two triangular faces is 60 cm2.
Next, find the area of each of the three rectangular faces using the formula, area = lw.
1st rectangle
a = lw
a = (5 cm) (5 cm)
a = 25 sq. cm
2nd rectangle
a = lw
a = (5 cm) (12 cm)
a = 60 sq. cm
3rd rectangle
a = lw
a = (5 cm) (13 cm)
a - 65 sq. cm
Add the three rectangle areas to find a total of 150 sq. cm.
To find the surface area of the triangular prism, add the area of the two triangular faces to the area of the three rectangular faces.
60 sq. cm + 150 sq. cm = 210 sq. cm
Answer:
Step-by-step explanation:
<u>The volume is:</u>
- V = Bl = 1/2(ah)l
- V = 1/2(7*8)*11 = 308 cm³
