Hi
bag containingmarbles: 8 green marbles and 12 blue marbles
draw one
P(green) = 8/20 = 2/5 (28/70)
bag containingmarbles: 5 green marbles and 9 blue marbles
draw one
P(green) = 5/14 (25/70)
25/70 < 28/70
As the fractional amount of green marbles decreases, there is less probability of drawing it