please explain the following simple probability question!?

Roulette is a game which has 38 numbers on a wheel 1 to 36 and 0 and 00 - American Roulette Wheel. The zeros are in a green color and the numbers 1 to 36 are either colored black or red. So there are 18 red numbers and 18 black numbers. If you land on a zero - you lose if you are just betting on red or black. so in two spins you can have

W,W

W,L

L,W

L,L

You have 4 different combinations that you can have in 2 spins

1 win win combination 2 win lose combinations and 1 lose lose combination.

so n=2 p=18/38 q=20/28 p=wins q=losses X= no of wins/loses

X Pr(X) probability distribution

0 (1)(18/38^0)(20/38^2)= (1)(1)(0.277)=0.277

1 (2)(18/38^1)(20/38^1)= (2)(18/38)(20/38)=0.499

2 (1)(18/38^2)(20/38^0)= (1)(0.22437)(1)=0.224

So the probability of zero wins is 0.277

The probability having a win and a lose in the 2 spins is 0.499 and 2 wins is 0.224. There is your probability distribution.