# probability: help needed

#### wnachifa

##### New Member
I need help with the following question:

At a raffle, 1000 tickets are sold at 4$each for five prizes of 400$, 300$, 250, 150$, 75\$. what is the expected value of a player's gain?

Here is my effort to resolve it:

Player chances: may win 1 ticket/ 2 ticket/ 3 ticket/ 4 ticket/ 5 ticket/ 0 ticket ( loose) . I can write the chances of winning as: 1/5, 2/4, 3/3, 4/2, 5/1, 0
1/1000, 2/999, 3/998, 4/997, 5/996.

i need to calculate the total of all probabilities:

win one ticket: (1/5) =0.2
win 2 ticket: 2/4= 0.5
win 3 ticket: 1
win 4 ticket: 2
win 5 ticket: 5

I am not sure if this is right because the total of my probabilities is way more than one .

if you kindly could throw any hint, i would appreciate it.

#### CJstatsman

##### New Member
Hi,

Expected values are always calculated by taking each outcome and working out how likely it is, then summing these values.

Don't forget to subtract you're initial spend!

Hope this helps, let me know how you get on,

CJ