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avatar+777 

Please explain the weird layout,  i have no idea how to approach

 Oct 28, 2018
 #1
avatar+4450 
+1

It's pretty straightforward.

 

P(X) must sum to 1.  You're given the first 4 values.  Determine the 5th.  The rest are 0.

 

\(E[X] = \sum~x p(x) = \sum \limits_{x=1}^4~x\cdot \dfrac{1}{x+2}+5k\)

 

Use the value of \(k=P(5)\) and evaluate that sum.

 Oct 28, 2018
 #2
avatar+777 
0

can u explain how k= 1/20 plz im still very confused, thanks

YEEEEEET  Oct 28, 2018
 #3
avatar+4450 
+1

the probabilities must sum up to 1

 

\(1 = P[1]+P[2]+P[3]+P[4]+P[5] = \dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6} + k\\ \\ 1 = \dfrac{20+15+12+10}{60}+k\\ \\ 1 = \dfrac{57}{60}+k\\ \\ k=\dfrac{3}{60} = \dfrac{1}{20}\)

Rom  Oct 28, 2018

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