Probability #1

[REL18]

In the process of cleaning out her closet, Susie found a book that she would like to sell. She has been offered $50 by a friend who would like to buy the book. However, after doing some research, she found out that if she sells it on E-bay she would have a 50% chance of getting $100, a 25% chance of getting $50 and a 25% chance of getting $10. There is a fee of $5 to sell the book on E-bay. Assume that Susie gets no benefit from helping her friend.

[ThinkQuick]

[ QUOTE ]
In the process of cleaning out her closet, Susie found a book that she would like to sell. She has been offered $50 by a friend who would like to buy the book. However, after doing some research, she found out that if she sells it on E-bay she would have a 50% chance of getting $100, a 25% chance of getting $50 and a 25% chance of getting $10. There is a fee of $5 to sell the book on E-bay. Assume that Susie gets no benefit from helping her friend.

[/ QUOTE ]

This kind of problem is a quite basic EV problem that you should be able to solve yourself if you are interested in learing poker math.

Also, you will get better repsonses in the DO YOUR OWN HOMEWORK forum
<font class="small">Code:</font><hr /><pre>
P = 0.5 you get 100 -&gt; 50
P = 0.25 you get 50 -&gt; 12.5
P = 0.25 you get 10 -&gt; 2.5

Total EV = 50 + 12.5 + 2.5 = 65
Total Profit = 65 - 5 = 60

60 &gt; 50 therefore sell on Ebay.

</pre><hr />

[REL18]

funny cuz u put u the wrong answer
$100 x .50 = 50ev
$ 50 x .25 = 12.50ev
$ 10 x .25 = 2.5ev

50+12.5+2.5= 65 65/3 = 21.666 The avg. price that Susie will get selling the book on ebay is $21.66-$5 (ebay charge) so she will on avg make $15.66 losing on avg 50-15.66 on sale
t wrong ansswer

[ThinkQuick]

[ QUOTE ]
funny cuz u put u the wrong answer
$100 x .50 = 50ev
$ 50 x .25 = 12.50ev
$ 10 x .25 = 2.5ev

50+12.5+2.5= 65 65/3 = 21.666 The avg. price that Susie will get selling the book on ebay is $21.66-$5 (ebay charge) so she will on avg make $15.66 losing on avg 50-15.66 on sale
t wrong ansswer

[/ QUOTE ]

mm. If you want to know something, I've read some of your other posts, about underage gambling, etc. , and I haven't yet gotten the impression that you are a valuable contributor to the forum. Despite this, I answered your darn homework question for you in the hopes that you would learn how to calculate expectation.

This forum is for learning. There is a lot that you can learn and a lot you're going to have to so sit your ass back and read - read a lot.

If you sell four books, you would expect to sell two for $100, one for $50, and one for $10. This means you have made $260 on four books.

I would say that this is equivalent to expecting 260/4 = $65 per book

You would say that this is equivalent to expecting 260/4/3 = $21.66 per book. Your way is wierd gorilla math.

Please take note: the only reason I am not shutting up and letting you submit your gorilla answer is in the hopes that you learn about EV and improve your poker, as you should on this site. Please take advantage of the opportunity.

[DoomSlice]

Expected Value is already sort of like a weighted average. When you divided by 3 at the end, you had already taken the average, and thus screwed up the math at this point.

Think's answer is correct.

[OrangeKing]

[ QUOTE ]
funny cuz u put u the wrong answer
$100 x .50 = 50ev
$ 50 x .25 = 12.50ev
$ 10 x .25 = 2.5ev

50+12.5+2.5= 65 65/3 = 21.666 The avg. price that Susie will get selling the book on ebay is $21.66-$5 (ebay charge) so she will on avg make $15.66 losing on avg 50-15.66 on sale
t wrong ansswer

[/ QUOTE ]

Wow. Can't you see this is wrong even with pure logic? If half the time she's getting $100 for the book, she'd be getting more than twice what you found even if she gave the book away for free the other half of the time. Although in that case, she'd be better selling it to her friend due to the ebay fees.

And of course, the mathematical explanation is above.