Answer:
6x+21
Step-by-step explanation:
Let us assume last year the price of the item = $x.
After increase in price by 15% the new price = x + 15% of x = x+ 0.15x = 1.15x.
There is a 25% discount for employee.
25% of 1.15x = 0.25 × 1.15x = 0.2875 x.
Price after discount = 1.15x - 0.2875 x = 0.8625x.
The employee pays $172.50.
Therefore,
0.8625x = 172.50.
Dividing both sides by 0.08625.

<h3>x=200.</h3><h3>Therefore, last year the price was $200.</h3>
Answer:



Step-by-step explanation:
Given

Solving (a): Point estimate of difference of mean
This is calculated as: 


Solving (b): 90% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 90% confidence interval is:

Solving (c): 95% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 95% confidence interval is:

Supplementary is when it is a straight line that is equal to 180 degrees and complementary is a right angle which is 90 degrees