You draw a marble from a jar containing 5 red marbles, 5 green marbles, and 6 blue marbles. Find the probability of drawing a green given that you did not draw a red.

Question

P(green | not red)

Answer 1

The formula for conditional prob is
Prob( A | B) = P(A and B)/P(B)

but you said you were drawing "a marble" suggesting only one is drawn.