Use the formula,
I = Prt
P = Principal amount = 400
I = interest = 18
r = annual rate
t = time in years = 9/12 = 3/4
so,
18 = 400*r*3/4
r = 0.06
so the annual interest rate is 0.06 or 6%.
The difference between the circumference of circle X and circumference of circle Y is 5π cm.
<h3>What is circumference of a circle?</h3>
This is the distance round a circle.
The circumference of circle X is calculated as follows;

The circumference of circle Y is calculated as follows;

The difference between the circumference of circle X and circumference of circle Y is calculated as follows;

Thus, the difference between the circumference of circle X and circumference of circle Y is 5π cm.
Learn more about circumference of a circle here: brainly.com/question/9782777
Answer:
8
Step-by-step explanation:
Note that √ signifies "square root."
If you're unsure of what √64 is, then make a short table of perfect squares until 64 comes up:
1 1
2 4
3 9
4 16
5 25
6 36
7 49
8 64
Thus, the square of 8 is 64 and so √64 = 8
Using it's concept, the standard deviation of the data is of 3.742.
<h3>What are the mean and the standard deviation of a data-set?</h3>
- The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.
- The standard deviation of a data-set is given by the square root of the <u>sum of the differences squared between each observation and the mean, divided by the number of values</u>.
For this data-set, the mean is:
M = (1 + 4 + 4 + 4 + 4 + 6 + 5)/7 = 4.
Hence the standard deviation is:

More can be learned about the standard deviation of a data-set at brainly.com/question/12180602
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Answer:
.3125
Step-by-step explanation: