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February 2nd, 2010, 07:37 AM   #1
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Expected Value & Probability

I have a 4-question worksheet and I think I have them all correct except for one:

1) A sorority sold 65 tickets in a raffle for a $480 TV set. What is the expected value of a single ticket if only one ticket wins?

- I'm stumped.

The other 4 questions I believe are correct--could someone confirm?

2) A box contains 4 blue cards and 3 red cards. If 2 cards are drawn one at a time, find the probability that both are red with replacement and without replacement.

- 9/49 with replacement
- 1/7 without replacement

3) Two dice are rolled. What are the odds against rolling a sum of 4 or 11?

- 31/5

4) In a NASA rocket firing, the probability of success of the 1st stage=70%, 2nd stage=56%, and 3rd stage=80%. What is the probability for success fir the three stage rocket?

- (70/100) x (56/100) x (80/100) = 196/625

Thank You!
mdenham2 is offline  
February 2nd, 2010, 12:19 PM   #2
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Re: Expected Value & Probability

For 1 hint: Buy all the tickets, how much should each ticket cost to break even?
2 and 4 are correct. 3 looks like a typo (31/5 ???)
mathman is offline  

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