did you ever get the answer?
Answer:
Step-by-step explanation:12 customers per hour..
4minutes per customer..
Time customers must wait= 12customers ×4minutes =48 minutes.. The clerk use 48minutes to attend to 12customers in one hour leaving him with 12spare minutes.
(B)since the clerk has 12 minute to spare it means each customer have a minute to wait before getting attention..
(C)number of customers waiting =12/2=6customers...
Answer: 
Step-by-step explanation:
For this exercise you need to use the following formula for calculate the area of regular polygon:

Where is "s" the length of any side, "n" is the number of sides.
Int this case you know that it is regular pentagon, which means that it has five sides. Then you can identify that the values of "n" and "s":

Therefore, substituitng values into the formula, you get that the area f the pentagon is:

Sin 3pi/4 is angle 135 degrees or 45 degrees below 180 degrees. Hence it's opposite side is 1 and adjacent is 1, implying the hypothenus is sqrt(2). Hence
Sin 3pi/4 = 1/sqrt(2). Now multiply by sqrt(2)/sqrt(2) to get:
[1/sqrt(2).] * [sqrt(2)/sqrt(2)] = sqrt2)/2
The answer can be readily calculated using a single variable, x:
Let x = the amount being invested at an annual rate of 10%
Let (8000 - x) = the amount being invested at an annual rate of 12%
The problem is then stated as:
(x * 0.10) + ((8000 - x) * 0.12) = 900
0.10(x) + ((8000 * 0.12) - 0.12(x)) = 900
0.10(x) + 960 - 0.12(x) = 900
0.10(x) - 0.12(x) = 900 - 960
-0.02(x) = -60
-0.02(x) * -100/2 = -60 * -100/2
x = 6000 / 2
x = 3000
Thus, $3,000 is invested at 10% = $300 annually; and $8,000 - $3,000 = $5,000 invested at 12% = $600 annually, which sum to $900 annual investment.