4.1
Games
Have you ever dreamed of becoming rich by gambling? You are not alone. Who really gets rich by gambling?
Today there are lots of games to bet money on, the lottery, horses, poker, sports, scratch cards and much more. Sure, there are lots of people who become rich at these games and who are lucky, but how much of a chance is there really?
There is always a sure winner in gambling, and it is those that organize the betting, the bookmaker. Every types of games work in reality in the same way. From the total bets on a certain game, the bookmaker always keeps a certain part and only pays out a part of the profits. It is quite self explanatory, otherwise the bookmaker would lose money and then no one would probably want to do the organizing.
How big of a chance is it to win?
We will look at a few examples where you can calculate the exact chance of winning:
Scratch Cards
Of the 2,000,000 “triss” scratch cards, there are about 400,000 winning cards. How big is the probability that you win on “triss”?
Probability = 
400,000 
=

1 


2,000,000 
5 
The probability to win is then 1 in 5 which sounds quite good.

Foto: Fredrik Enander 
Lottery
In the lottery, 7 numbers are drawn between 1 and 35. In order to win the highest pot, you need to have all 7 correct. How big is the probability of doing that?
When calculating, you need to remember that a number has disappeared when the next one is drawn.

Foto: Fredrik Enander 
1^{st} and 2^{nd} number = 
7 
· 
6 


35 
34 
All the numbers = 
7 
·

6 
·

5 
·

4 
·

3 
·

2 
·

1 
= 
5,040 








35 
34 
33 
32 
31 
30 
29 
33,891,580,800 
The probability of getting 7 right is then 5,040 in 33,891,580,800, or if we simplify 1 in 6,724,520. Not then a great chance.
