Answer:
The diameter of a circle with an area of 100 square miles is 20/√π miles.
Step-by-step explanation:
Area =100 = πr^2.
diameter = d = 2r.
100 = πr^2.
100/π = r^2.
√(100/π) = r.
10/√π = r.
d = 2r.
d = 2 * 10/√π.
d = 20/√π
when x = 1, f(1) = 1/3
Answer
1/3 or 0.3333 (3 is repeating)
Answer:
a

b

Step-by-step explanation:
From the question we are told that
The mean value is 
The standard deviation is 
Considering question a
The sample size is n = 9
Generally the standard error of the mean is mathematically represented as

=>
=> 
Generally the probability that the sample mean hardness for a random sample of 9 pins is at least 51 is mathematically represented as



=> 
From the z table the area under the normal curve to the left corresponding to 2.5 is

=> 
=> 
Considering question b
The sample size is n = 40
Generally the standard error of the mean is mathematically represented as

=>
=> 
Generally the (approximate) probability that the sample mean hardness for a random sample of 40 pins is at least 51 is mathematically represented as

=> 
=> 
From the z table the area under the normal curve to the left corresponding to 5.2715 and
=> 
So

=> 