Answer:
20. 4n+5+8n-5=180(linear pair)
12n=180
n=15
21. 9x-6=8.5x+2(can be seen from image)
9x-8.5x=2+6
0.5x=8
x=8/0.5
x=80/5
x=16
22. 4z+3z+6=90°(Complementary)
7z+6=90°
7z=84°
z=12°
Answer:
A sample of 18 is required.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Z-table as such z has a p-value of 
.
That is z with a pvalue of 
, so Z = 1.88.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
A previous study indicated that the standard deviation was 2.2 days.
This means that 
How large a sample must be selected if the company wants to be 92% confident that the true mean differs from the sample mean by no more than 1 day?
This is n for which M = 1. So
Rounding up:
A sample of 18 is required.
V=1/3*πr² *h,
raduus r=32/2=16
V=1/3*3.14*(16)² *18=6*3.14*(16)² =4823.04
Answer:
To convert a quadratic from y = ax2 + bx + c form to vertex form, y = a(x - h)2+ k, you use the process of completing the square.
Step-by-step explanation:
Answer:
3/10
Step-by-step explanation:
Multiples of 3: 3,6,9,12,15,18
There are 6 in the numbers 1-20
P(multiple of 3) = number of "multiples of 3" / total
= 6/20
=3/10
