Question

You choose to participate in a raffle. Raffle tickets sell for $5 each and there are a total of 10,000 tickets. The prizes in this raffle are:

1st prize: $20,000 college scholarship (1 winner)
2nd prize: $10,000 college scholarship (2 winners)
3rd prize: $1,000 college scholarship (5 winners)
4th prize: $100 college scholarship (50 winners)

You purchase one $5 raffle ticket. How much of your college tuition can you expect to be paid for by your raffle tickets purchase?

Answer 1

@ganeshie8

Answer 2

ribhu do you have any idea

Answer 3

@ganeshie8 when i calculated it i did this:
(-5* 9942/10,000) + (20,000 * 1/10,000) + (10,000* 2/10,000) + (1,000*5/10,000) + (100*50/10,000)=

-4.971 + 2 + 2 + .5 + .5

And this was my answer but i know its wrong so i don't no what I'm supposed to do: .029

Answer 4

0.029 looks good to me
how do you know it is wrong ?

Answer 5

Ahh no wait, you forgot to subtract the ticket cost..

Answer 6

try this :
http://www.wolframalpha.com/input/?i=%28-5*+9942%2F10%2C000%29+%2B+%28%2820%2C000-5%29+*+1%2F10%2C000%29+%2B+%28%2810%2C000-5%29*+2%2F10%2C000%29+%2B+%28%281%2C000-5%29*5%2F10%2C000%29+%2B+%28%28100-5%29*50%2F10%2C000%29

Answer 7

ohhh i thought the ticket cost was just multiplied by the first answer so should i do 5-.029?

Answer 8

No, the random variable here is "net profit"
so you need to subtract "5" from each of the prize value

Answer 9

oh ok so i do-4.971-5 + 2-5 + 2-5 + .5-5 + .5-5?

Answer 10

Nope

Answer 11

then wht is it. I cant get it

Answer 12

1st prize: $20,000 college scholarship (1 winner) `(20000-5)*1/10000`
2nd prize: $10,000 college scholarship (2 winners) `(10000-5)*2/10000`
3rd prize: $1,000 college scholarship (5 winners) `(1000-5)*5/10000`
4th prize: $100 college scholarship (50 winners) `(100-5)*50/10000`

Answer 13

add them up :

`(20000-5)*1/10000` + `(10000-5)*2/10000` + `(1000-5)*5/10000` + `(100-5)*50/10000`

Answer 14

ok i got 1.9995+ 1.999 + .4975+.475= 4.971

Answer 15

also add probability of -5 : 9942*(-5/10000)

Answer 16

ok for that i got -4.971

Answer 17

` (20000-5)*1/10000` + `(10000-5)*2/10000` + `(1000-5)*5/10000` + `(100-5)*50/10000` + `9942*(-5/10000)`

Answer 18

adding them all gives you 0
so the expected value is 0

Answer 19

really? thats not one of my answer choices which is why I'm getting so confused, the answers are:

A. -$10.20
B. $5.00
C. $4.56
D. -$3.72
E. $100

Answer 20

@jim_thompson5910 @perl could you help me with this problem please?

Answer 21

The expected value is 0 after the inclusion of the cost of the ticket. I think your teacher made a mistake. Select B and tell him/her.