that is only for the first selection, once the first marble is removed from the group the odds change.
The first set of odds is what is the chance of one of fve marbles being drawn from a total population of 30 - one ins six
If it is white it is what is the chance of drawing one of five marbles form a total of 29.
Break it down. I have 6 marbles and one is black.
I draw one white marble - my chances now are one in five.
I draw another white, my chances are now one in four, I draw another white it is now one in three I draw another white and it is one in two. I draw another white and my last chance is one in one. there is only a black marble in the bag
I refill the bag with all marbles I draw the first marble and it is black - I have no chance for the last five draws. favourable unfavourable draw white black odds 1 25 5 5 1 2 24 5 5 1 3 23 5 5 1 4 22 5 4 1 5 22 4 6 1 6 22 3 7 1 7 21 3 7 1 8 21 2 11 1 9 20 2 10 1 10 19 2 10 1 11 18 2 9 1 12 17 2 9 1 13 16 2 8 1 14 15 2 8 1 15 14 2 7 1 16 13 2 7 1 17 12 2 6 1 18 11 2 6 1 19 10 2 5 1 20 9 2 5 1 21 8 2 4 1 22 7 2 4 1 23 6 2 3 1 24 5 2 3 1 25 5 1 5 26 5 0 27 4 0 28 3 0 29 2 0 30 1 0
