# I just wanna say thanks..

• Mar 1st 2009, 07:12 PM
SMS386904
I just wanna say thanks..
I have never found a forum where people are nice enough to help you out as people do on here... it's greatly appreciated... with that said one more question, lol:

The Book Sweepstakes mails 20,000,000 entry forms of which

Winnings 3 10 500 5000 10000 25000 100000

Number 12000 7900 90 4 3 2 1

If you enter this sweepstakes, what is the probability that you will win something? Is your expected return more than the cost of mailing a first class letter?
• Mar 1st 2009, 08:01 PM
Chris L T521
Quote:

Originally Posted by SMS386904
I have never found a forum where people are nice enough to help you out as people do on here... it's greatly appreciated... with that said one more question, lol:

The Book Sweepstakes mails 20,000,000 entry forms of which

Winnings 3 10 500 5000 10000 25000 100000

Number 12000 7900 90 4 3 2 1

If you enter this sweepstakes, what is the probability that you will win something? Is your expected return more than the cost of mailing a first class letter?

The probability that you will win something is $\displaystyle \frac{12000+7900+90+4+3+2+1}{20000000}=.001$

Now, the expected payout would be

$\displaystyle 3\left(\frac{12000}{20000000}\right)+10\left(\frac {7900}{20000000}\right)+500\left(\frac{90}{2000000 0}\right)$ $\displaystyle +5000\left(\frac{4}{20000000}\right)+10000\left(\f rac{3}{20000000}\right)$ $\displaystyle +25000\left(\frac{2}{20000000}\right)+100000\left( \frac{1}{20000000}\right)=0.018$

So your earnings would be less than the cost of mailing a first class letter.

Does this make sense?