Answer:
a. E(x) = 3.730
b. c = 3.8475
c. 0.4308
Step-by-step explanation:
a.
Given
0 x < 3
F(x) = (x-3)/1.13, 3 < x < 4.13
1 x > 4.13
Calculating E(x)
First, we'll calculate the pdf, f(x).
f(x) is the derivative of F(x)
So, if F(x) = (x-3)/1.13
f(x) = F'(x) = 1/1.13, 3 < x < 4.13
E(x) is the integral of xf(x)
xf(x) = x * 1/1.3 = x/1.3
Integrating x/1.3
E(x) = x²/(2*1.13)
E(x) = x²/2.26 , 3 < x < 4.13
E(x) = (4.13²-3²)/2.16
E(x) = 3.730046296296296
E(x) = 3.730 (approximated)
b.
What is the value c such that P(X < c) = 0.75
First, we'll solve F(c)
F(c) = P(x<c)
F(c) = (c-3)/1.13= 0.75
c - 3 = 1.13 * 0.75
c - 3 = 0.8475
c = 3 + 0.8475
c = 3.8475
c. 
What is the probability that X falls within 0.28 minutes of its mean? 
Here we'll solve for
P(3.73 - 0.28 < X < 3.73 + 0.28) 
= F(3.73 + 0.28) - F(3.73 + 0.28)
 = 2*0.28/1.3 = 0.430769
= 0.4308 -- Approximated
 
        
             
        
        
        
It’s 54.8 I’m pretty sure 
(I hope this helps!)
        
                    
             
        
        
        
<h3>

 is the simplified expression</h3>
<em><u>Solution:</u></em>
Given that,
We have to simplify

We can simplify the above expression by combining the like terms
Like terms are terms that has same variable with same exponent and same or different coefficient
From given,

Group the like terms

Thus the given expression is simplified
 
        
        
        
Simple...
you have: 

To make this into an improper fraction-->>
1.) Multiply whole number by denominator
2.)Add the number you got plus the numerator
3.) Use the original denominator to finish your improper fraction
Example: 

4*9=36
36+4=40

Thus, your answer.
 
        
        
        
The correct answer would be at and t because its cheaper  for 50 text