The answer is 
7.9306Using the formula in the attached:
Where: xi = sample value; μ = sample mean; n = sample size
1.) Calculate the mean first:
μ = 12.0 + 18.3 + 29.6 + 14.3 + 27.8 / 5
   = 102 / 5
μ = 20.4
2.) Using the mean, calculate (xi - μ)² for each value:
(12.0 - 20.4)² = 70.56
(18.3 - 20.4)² = 4.41
(29.6 - 20.4)² = 84.64
(14.3 - 20.4)² = 37.21
(27.8 - 20.4)² = 54.76
3.) Sum the squared differences and divide by n - 1.
μ = 70.56 + 4.41 + 84.64 + 37.21 + 54.76
   = 251.58 / 5-1
μ = 
62.895 (this is now called sample variance)
4.) Get the square root of the sample variance:
 √62.895 = 
7.9306
 
        
        
        
Answer:
x=10^{\frac{2}{3}}-5
Step-by-step explanation:
 
        
             
        
        
        
Answer
The answer and procedures of the exercise are attached in the following archives.
Step-by-step explanation:
You will find the procedures, formulas or necessary explanations in the archive attached below. If you have any question ask and I will aclare your doubts kindly.  
 
        
             
        
        
        
Answer:
A. 26 1/2
Step-by-step explanation:
change denominator so they can be the same 
3/4*3  =   9/12
1/3*4   =   4/12
Add the whole numbers : 10 +15=25
9/12+4/12= 13/12 so 1 1/12
26 1/12