13,822 to one significant figure is 10,000
623 to one significant figure is 600
14 to one significant figure is 10
10,000 times 600 = 6,000,000
6,000,000/10 = 600,000
I'm not going to do the entire question, but I'll do the first part.
For the first part, you have to set up an inequality. Use context clues, such as
no more than (the one used in this sentence) to figure out what the symbol should be for the inequality.
In this case, because it is NO MORE THAN 6400, it would be:
6400

250r + 475p
where r represents the # refrigerators, and p represents the # pianos
Now that you have the equation, make the graph, then for the 3rd part, plug in 12 and 8 to r and p to see if it keeps the inequality true.
Hope this helps! :)
Answer:
Sample size minimum is 60
Step-by-step explanation:
given that you want to create a 99% confidence interval with a margin of error of .5.
The population standard deviation is equal to 1.5
i.e. 
Confidence level = 99%
Since population std deviation is known, we can use Z critical value for finding margin of error
Z critical value for 99% = 2.58
Margin of error = 
Equate this to 0.5 and solve for n

Answer:
3876
Step-by-step explanation:
Given the following :
Fraternity members = 20
They are to attend 5 different parties in groups of 4
Meaning a group = 4 persons
Atleast one brother will attend exactly one of the parties. (the brothers are indistinguishable).
Then, exactly one brother at a party (20 - 1) = 19, since they are indistinguishable.
Group members are in 4's
19C4
From: nCr = n! /(n-r)! r!
19C4 = 19! / (19 - 4)! 4!
= 19! / 15! 4!
= (19 * 18 * 17 * 16) / (4 * 3 * 2)
= 93024 / 24
= 3876
The answer is C. x<span> ≤ </span>3